Hi all,

Long time lurker, first time poster, just want to say first off that I've learned so much (and gotten an equal amount of anxiety!) from many of the threads and posts on this particular forum.

So the reason for this first post—as alluded to in the title—is that I've got a line on a high mileage GT4 (61,000 mi…yes, that's miles, not kilometers). It was part of an exotic car rental fleet, however it was well maintained by a garage of 3 full-time mechanics, has a good service history, clean title, and never tracked. The only things that are really wrong are the parking brake warning shows up every now and then, one of the windshield nozzles is FUBAR, and the driver's side window switch module needs replacing. PPI is pending, and while I'm sure the DME will show some interesting stats, I'm 98% confident this car is a solid runner. It's definitely seen more roads than most of the GT4s out there, but you'd never know from driving it (which I have recently).

And therein lies the problem I'm facing: "most of the GT4s out there" are under 15,000 mi, mint condition, stored in a nice garage, and rubbed gently with a diaper from time to time. As such, I don't really think the major valuation sites (KBB, Edmunds, etc.) are actually able to price this market correctly, so I went ahead and did it myself. I've scraped pricing and mileage data from about 190 online listings (the usual suspects: Mecum, eBay, Carfax, Porsche CPO, Bring a Trailer, and Rennlist sales from 2018 and 2019 [thank you for keeping all that pricing data intact!]), and put together a dataset that could be used to generate a couple different trendlines. It's this data that I'd like to use in my negotiations with the seller, however I wanted to get a reality check from the good folks of this forum to see if y'all think I'm on the right track, or completely bat****.

See here for a PDF of the graph output.

I used this aforementioned dataset to generate 2 trendlines: one with an exponential slope (more gradual, roughly representing the average price), and one with a linear slope (steeper, could be thought to represent a lower price boundary). From these I was also able to derive a dollar per mile decrease in price of $750 per 1000 miles driven (i.e. a rough depreciation proxy). This is referencing an older version of the graph; see below for updated info.

Using this dataset, I generated an exponential trendline with a 95% confidence interval (and the associated upper- and lower-bounds). Also, by sampling prices at 2500 mile intervals along the main trendline and calculating the mean average of those prices, I came up with a dollar per mile decrease in price of $808.50 per mile driven.

Some things I've kept in mind when compiling and looking at this data:

1. This is a mix of asking prices and sale prices. And while I’ve combined these in the data, on average the asking and sale prices of cars with similar mileage are within about 2-3% of each other, so I consider the difference a wash.
2. This doesn't control for trim and options. So some of these have carbon ceramics, sports chrono, and carbon buckets, while others have 18-way power seats, steel rotors, and no options on the interior trim. On the whole I think the two extreme ends balance each other out.
3. The vast majority of these are less than 15,000 mi, so very much skewing towards garage queens / weekend cars (with a sprinkling of track cars in there, I’m sure, but I don't feel like it'd be enough to outweigh the mint condition GT4s).
4. The 2018 Rennlist values are a bit higher than 2019, but not by much: a mean average of $104,187 for 2018, and $96,615 for 2019. I was worried that the some prices that people were seeking in 2018 might skew the data, but it's only a 7% difference so I'm comfortable including that into the data. It seems like the 718 GT4 announcement didn't take a huge dent out of the 981 GT4 market like some were thinking it would.

So basically what I've come away with is this: this 61,000 mile car, if it were in absolute mint condition, could command a market price of $57,000 between $56,750 and $66,650. However, given the fact that it's lived its life as a fleet car—and all the issues that are part and parcel of that life—I feel like $50–54k is a more fair assessment value-wise. Is this reasonable? Should I go full-on shrewd negotiator and start the asking at $48k? Are my numbers complete bull**** and I'm living in a fantasy land? Does any of this really matter (I mean, according to Freddie Mercury, nothing really matters, but that's a different song for a different day…)?

I should mention in the name of completeness that KBB pegged this at $64,838, and Edmunds had it as $56,762 (I hadn't looked at those numbers in a while…maybe Edmunds does know how to price this market…)

Thoughts, concerns, rebuttals—I welcome one and all, and look forward to the wisdom of the crowd.

 

The DME readout would be critical. It would also be interesting to know whether the transmission has been replaced for the 3rd gear recall. It would be more attractive if it hasn't been because it would give you an opportunity to have a fresh transmission and pay for a new clutch. If you can get the car for half of new MSRP (i.e. $55-60K) with a new transmission and a DME without any seriously concerning hits, it would be a steal.

 

I love your graph! The engineer in my loves looking at this data.

I think the above quote is probably your biggest source of error in the data. The MSRP on these cars could have varied widely from $87k to $130k. That definitely sways the second hand selling price. I wonder if you could look at the data as "Price under MSRP vs miles"? That may yield better results.

Thats just my $0.02

 

I think given the life this car has had, the DME will definitely throw up some interesting numbers. Honestly though, at this price it’s a trade off I’m willing to consider.

This was an early production car (06/2015), so it shouldn’t be affected by the 3rd gear issue, however I’ve heard some early production gearboxes still getting replaced? Or am I misremembering?

 

My take is that any rental cars, including exotics, will need quite a bit of attention to get to a satisfactory condition. These cars are NOT garaged and it needs at least a thorough detailing. Secondly, you might not discover all the little problem areas during an initial test drive, but believe me once you get familiar with it, these issues will crop up. This car is /was a rental and no self-respecting renter is going to treat it with kids' glove and although 60K miles is not high, but those are fairly rough mileage because it is a rental.

 

Do you really want a GT4? For that money you can find a mint Cayman R with practically no miles and potentially CPO. The street fun factor for these cars is near the same. Both are special and unique in their own ways. The Cayman R is actually going back up in value these days, not down, and is on Sothesby's watch list for a future classic. I've owned both (both were at the top of their respective MSRP range) and I wish I could swap my GT4 (which I still own) for my old Cayman R as in my opinion it's a better street car, and no slouch on the track either.

Austin Porsche has a nice one they've had for a while. $75k but it's over-priced a bit. 8k miles and CPO.

Just a thought...

 

Do you have the DSC Sport Controller for your GT4? If you're looking for a more compliant street ride, it would be a nice way to go. It's taken about 2 months of trial and change, but I think I've got both Normal and Sport settings I'm happy daily-ing over the potholed, rutted, two halves of same lane on 2 different angles for 15 mile stretch of I-66 in my area.

For the OP, FWIW, I just purchased my 31k mile CPO example this summer, w/$108k window sticker, from a Porsche dealer who asked $86k. I thought about trading for an Audi, and the Audi dealer happened to work with the Porsche dealer where I bought it. After 4 months and 3k miles added, the dealer only offered $67.5k. I just did a trade value on kbb.com and it came up with a trade value that split the difference. At the time, mine was the highest mile by 2x of all the GT4s found on Porsche's site....seemed like depreciation was closer to $1k per 1k miles driven, off original MSRP, for all the cars.

 

I'm about ready to try the DSC sport controller. I don't think the GT4's suspension is anything as stiff as a BMW M series, but I love X73 and the GT suspension is way more harsh. Seems overall everyone with the DSC controller thinks it's worth it, but some say it makes little difference on the street and others seem to think it's a bit more than that. I was waiting for DSC to offer a holiday discount, which they alluded to a few months back. I haven't seen anything. Probably wouldn't have been much of a discount anyway, but had they not made mention I probably would have already bought one.


Sorry for the off-topic escapade but GT4 ownership does come with issues.

 

Another engineer here approving of your graph and data forward approach... Very interesting!

One thing that jumps out at me is that you are assuming a purely linear depreciate curve which we know it is not. It looks like your tool would predict a value of zero dollars at roughly 120k miles. There is no way that would happen. There must be some bottom to the depreciation assuming the car is properly maintained. So what would a 300k mile GT4 be worth in perfect running condition? It would not be zero. Total guess but maybe $30k? It may have some wear and tear but it would still make a great track car. If it was in perfect running condition there would have been a lot of money spent on it. Maybe a fully rebuilt engine and tranny? So if you set something like $30k as your min price asymptote maybe you could manually sketch a curve. Of course that would not favor your negotiation but it is likely more realistic.

 

I think that instead of plotting absolute price, that I would plot percenage of MSRP. Its also a flawed approach but I believe that it is less flawed than actual price. Date of sale is a confounding factor as well.

I like data driven approaches to cars too!

 

You're the second person I've spoken to that's mentioned the Cayman R. I think for me the GT4 in this particular situation is simply just being able to get one of these at this kind of price. So it's partly "this is a great car and I absolutely love it every time I've driven it" and partly value for money. Collectability isn't really a priority for me (not knocking it for those that value that, though!)


I've actually looked into this as a way of potentially making the car more livable day-to-day and was curious if it was worth it. Sounds like it is from your experience!


Interesting about the depreciation value, I'll have to chew on that a bit. And thanks for the info on your sale—I'll have to add yours as a data point in my set.


Happy to hear appreciate this approach! This is exactly the kind of hole-poking I was hoping for. In all honesty this is all simply from data I've plugged into Excel and then generated trendlines off of, so there's nothing super fancy going on (the data is doing the work, not me). I'll freely admit that the "deprecation curve" was simply just a function of taking the median price value @ 61k miles and drawing a straight line from there to the origin of the other trendlines. So it was never truly meant to represent real-world depreciation, rather just a way of getting at a rough estimate for this particular situation. So a question for you here: if I were to approach the seller (who's also an engineer, incidentally) with this data, would my case be stronger or weaker if I were to include that "deprecation curve"?

 

The fact that it is a rental car is what would make me want a greater percentage off. The cars with 40k miles seem to be selling in the $70s. So maybe $50s or $60s as you are saying for 70k miles. However, these cars will eventually come to a point where they won't really depreciate anymore. A GT4 is never going to be a $20k car unless it has 100k miles and a salvage title.

 

Was it mentioned how much the seller is asking for it? I think that would factor into this particular negotiation, but not the full market analysis

 

We’re still waiting on the PPI before discussing figures as those results will likely have an effect on the price.

 

It all depends on what you want it to do, and how you configure it. TPC offers great support, so you can sort of "micro-configure" to really get it where you want it. Had I not known about, and bought the controller, I would not have kept the car after only a few weeks, because of the suspension alone. I was able to change all of the dislikes I had with the stock suspension as well as the setup that was pre-loaded from DSC. I basically went from feeling like I wanted to swap out the whole suspension, to leaving everything as it was when I bought it (ride height, etc, which I initially felt may have been too low) and feeling like I could set it up to where I have 2-3 totally different full suspension kits installed at any time, just by swapping config files.

I will probably not see much track time, if any, so I basically have "Downtown Philly", and "Spirited smooth country road drive on the other side of my town, but can still smooth out a nasty bump at speed" modes to toggle between. If/when I do get it on track, I can always load a track focused file when I arrive, then flash back for the ride home.