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I'm sure this info is out there are various Threads including an active one which I've read through on part of this topic, but I'd like to look at options for my situation and value opinions and real estimate$. I have an 07 .1 RS That I plan to keep forever... 26k on the clock. I only use it for spirited mountain drives and occasionally around town. I see the track with this car maybe 1X per year so that is not the focus (because race car). I plan to do the Dundon Plenum and take care of Pinning the coolant lines, also update the suspension to an MCS variant of some type... etc..
Question is what should I do keeping cost, and use of the car in mind:
What Diff
What Ring Pinion Set-up
What mounts (I understand Sharkwerks has an option here)
What else? Clutch?
I'm not an expert on the 7.1 GT3 RS... But if it has the same gearing as the base GT3, I would change the gearing to match the 7.2 RS. To swap the ring gear and refresh my gear box was about $10k from Copans including the parts. I added some urethane to the gearbox mounts to fill in some of the voids, but I didn't go crazy with mounts. Everyone's favorite mod is the loudest lightest flywheel and clutch combo they can get... Not mine though. I kept the dual mass and have no regrets. Your car may already have the light flywheel from the factory?
Based on your usage, I wouldn't do anything unless you have dollars to burn willingly. Keep it OEM and running strong. Surprisingly Porsche does a decent job engineering vehicles, it's much easier to make these cars worse than it is to make them better.
Diff - you drive on the street, one could argue having a worn diff is more fun/lively, easier to get the car to step out
- If you want a functional diff, rebuild with Guards diff parts, cheapest option $2300 in materials, remove and replace another $2000
R&P - you drive on the street, do you feel that your car is slow and needs more torque?
If you want more punch off the line, low speed corners, R&P can be worth it, but to do it "right" and actually get the performance benefits, I think you refer to the other post. Seems like the range is around $15K
Motor mounts - you drive on the street, do you want more noise and vibration? are you lacking a sense/feeling of mechanical connection between the chassis and motor? Go with OEM for your needs
I think this is a personal preference, I'm not a fan of solid mounts for street use. There are some stiffer alternatives from OEM to aftermarket. Personally, I'd use a Porsche mount that is stiffer than the existing. $1000
Clutch - you drive on the street, do you want more noise and vibration? do you feel that the vehicle is not "free revving" enough for you? Is the rotational mass holding you back somehow? The 3.6 is pretty rev happy in comparison to the 3.8.
Unless your clutch is slipping, there is no mechanical need for replacement. If you choose to and don't mind a little more N&V then 4.0 is the way to go. $4000 in parts, R&R $1500
Suspension - you drive on the street, do you want a more comfy ride or reduced lap times? IMHO unless you go Ohlins TTX or other full motorsport (2,3 or 4 way) suspension don't bother.
TTXs are $8,000, you get what you pay for when it comes to suspension anything around the $2-4K isn't going to be much better than OEM, IMHO
Dundon Plenum - you drive on the street, the speed limit is less than 80mph. Are you lacking power? $8K for 40hp is cheaper than a motor build but why?
If money is not object do all of it, but at that point, just have a 4.1L built, get some TTX's, rear gear, 4.0RS clutch, Guard chromoly diff and while you're at get some CGT seats too. Again, just my opinion, labor rates vary from shop to shop, but this is around what I would expect to pay in SoCal at fair rate independent trusted specialist.
Yes I drive on the street. I'm not far from the Smokies so its driven hard in the mountains. It is lacking power compared to what I drive daily and the gearing is too tall IMO 2nd-5th. So my thought is shortening the gearing to make it quicker. Plenum, gearing, Diff will liven up the car in general. I do not want a race diff that will make feel like it is understeering, but I've heard that the correct Diff can help.
Clutch is a LWFW from the factory in an RS so no need in a 4.0L clutch for the cost assuming mine is in good shape.
Suspension, it old and I feel an upgrade would soften the bumps when needed but be more responsive and planted when pushed.
Mounts. I do not want a race car and I do not want it to ride like a telephone poll; but with the age of them and while everything is out perhaps replace with a better stiffer urethane, but not hard mounts.
I’ll say bang for the buck the MCS Single Adjustable are great. Smooth where you need, more complaint, not any faster on track but smoother and a nice refresh if shocks are letting go.
Diff is a MUST imo. A car with a shot lsd sucks and we all know they go quick. I actually never even loved the 997gt3 until I drove one with a guards rebuild. I sold 2 previously very quickly as they all have shot Diffs after a track day or some miles. I have kept my current one which came with guards internals. There is so much more rear end feel. Guards is the answer. Think everyone around here will say the same.
I also think the exhaust valve mod is a must if you don’t have some crazy aftermarket exhaust. I just have a center delete and the fully open valve is so much better at low rpm
I replaced the R&P on my 997.1 RS to a Porsche 3.89 unit. Also changed 6th gear to match the 997.2 changes. Replaced the clutch pack, new Guard 40/60 guts, and RMS. Including shipping and R&R at my local independent, about $12-14k. That was five years ago, so likely more now. Really changed the character of the car for the better. Leaves from a dead stop easier, and acceleration is substantially improved. Not cheap but worth the cost for a keeper car. I’ve had mine for about twelve years now.
Last edited by HarmonyJim; 05-12-2023 at 10:56 AM.
The ring and pinion completely changes the car. It makes it much more lively and fun on the street. Something about 2nd gear going over 80mph bothers me in any car. It paired with a LWFW will be an amazing set of upgrades. If you aren't tracking the car a ton i would consider a LSD rebuild with a guards clutch pack over a full new unit.
As for mounts, i have the Rennline tunable set and they are great. Very easy to swap and a choice of inserts.
I replaced the R&P on my 997.1 RS to a Porsche 3.89 unit. Also changed 6th gear to match the 997.2 changes. Replaced the clutch pack, new Guard 40/60 guts, and RMS. Including shipping and R&R at my local independent, about $12-14k. That was five years ago, so likely more now. Really changed the character of the car for the better. Leaves from a dead stop easier, and acceleration is substantially improved. Not cheap but worth the cost for a keeper car. I’ve had mine for about twelve years now.
Remind me on the 997.2RS vs. rest of 997 gearbox. It was the 3.89 final drive and a taller 6th right? Or were the other gears restacked with different ratios?
I’m debating if its time to refresh my gearbox… 1st can be a little grumpy when cold… if I do its a while in there thing as since its an around town canyon toy, well why not… already have the Guard billet diff.
3.8RS R&P if you can find one
OE Clutch, if you want a 4.0RS LFW and clutch then do a harmonic Damper at the same time
No Politics Racing Torque Flow Diff
MCS 3 way dampers
Weld Coolant fittings
Sharkwerks or BBI machined side fittings
Dundon Street headers
Resonance Intake Manifold
Cobb Tune