When I first drove a 996 I thought it felt a little "floaty". My car at the time was a 98 M3, which felt solid, hunkered down and aggressive. Subsequent drives in the 996 changed my mind completely. Yes, it was much lighter and more delicate to the touch but these were qualities I rapidly came to appreciate and value. I found that I could take familiar corners on the way home much faster than I had been used to, turn in much more sharply and quickly, and almost dance with the car. The M3 was much less a dancing partner - more a trusty charger/steed. As much I enjoy my new 996, I believe it still needs to be lowered and stiffened. It still floats a little too much for my taste and understeers too much - a kind of unpleasant GT feel. So, without further ado, what should one do?
Porsche's own sports suspension package substitutes stock springs with MO30's. Be sure to order the right set (US or RoW). Spring plates differ by market and I believe C2s and C4s are also different. It may well be that you can fit RoW MO30's, which are stiffer than the US part, to a US car but make sure before buying. The car will be lower by about 20mm front and 10mm rear. Some report that there is a mismatch between these springs and the stock shocks, resulting in a slight bouncing effect. This has not been confirmed by enough people to be a definitive issue however. In the order of stiffness, most other springs are likely to be stiffer than these, although a Tech at H&R claimed that the MO30's would give a greater stiffness than shorter springs, such as their own progressive spring package for the 996, due to the fact that they have greater distance in which to exert their springiness. This seems like a strange remark to me... but I'm not a spring guru like this guy was supposed to be.
You WILL feel a harsher ride with almost any sport suspension, so if you are hestitant at all, try to hitch a ride with someone who has already made the change and see if you are willing to make the trade-off (comfort vs. performance). I took a ride in Bill (Chicago)'s C2 which has H&R's and the ride was just fine. For my taste, not harsh in the slightest and giving a much flatter ride through corners. Bill reports that his H&R's are great on the track due maily to lowered center of gravity and a tightness when under pressure but that in normal driving over rough roads they are not well matched to the stock shocks giving an occassional mild bouncing effect.
There appear to be four significantly favored alternatives to MO30's: H&R, TechART, Eibach, and JRZ.
H&R springs are extremely well-known to enthusiasts the world over. The standard springs (H&R only make one set for the 996) correct understeer somewhat, lower the car (about 30mm) and feel stiffer through twisties when pushing hard. Most seem to be very happy with them but some feel these springs are too stiff/harsh. It all depends what you like. My personal view is that the car needs stiffer springs and that H&R's are almost identical to stock - really not stiff enough. The fact that they lower the car helps, however, and will keep the car flatter through turns. If you like a "touring" ride, stick with stock. (H&R has an official coilover kit for the 996 which will be formally released towards the end of 1999. Others have created their own H&R based coilovers, using, I think, Bilstein shocks.) Tire Rack sell H&R's and are one of the cheapest suppliers.
TechART springs lower the car by about 20mm. Reports are scant on performance but these springs may provide a nice balance somewhere between H&R's and Eibachs. You should expect about $360 for the set plus $400 for install and realignment.
Eibachs, typically coupled with M30 Bilstein shocks, are known in BMW circles to give many of the handling characteristics of a sport set up without being as harsh as H&R's. At least one Board member has this set up and likes it. It would appear to be a good compromise if you are not a die-hard D.E. type.
Of course, if you really, really want the best available, then JRZ's or the Penske Double Adjustables (used by Kelly Moss on their 996 race car) might just be your ticket to suspension bliss. The JRZ's come in at least 2 flavors - single adjustment and doubles (for bump and rebound). There may also be a triple adjustable version. A few of us have or are getting JRZ's, mostly the single adjustables. Here's what Todd Serota, who has no affiliation with JRZ, has to say about them:
"In a word - AWESOME!!
First, some details. I added 14-position, single adjustable (rebound) JRZ shocks and Faulkner (of F1 racing fame, from England) springs - 450 lbs rear, 400 lbs front (as compared with about 200 rear and 175 front, I believe, for my M030 springs), purchased from Joe Fabiani at Fabspeed. I could have lowered the car any amount I chose (within reason), and I decided to lower it about 35 mm in the front and 30 mm in the rear. Here are my impressions.
Looks - amazing! It looks like a different car - more like an older Speedster (obviously without the lower raked windshield and rear bubble). It's incredible what a huge difference an inch or so can make. Now there is no space between the top of the tires (18's) and the bottom of the wheel wells. At lunch, I happened to park right in front of another 996 Cab at stock ride height, so I could look at both cars from the side at the same time. Much better.
Feel- what a difference! I already had the 996 Supercup adjustable anti-sway bars, which helped to flatten out handling, but there was still noticeable body roll as compared with a full-on race car. Now, the car feels almost dead flat in transition. I did some quick lane changes back and forth at about 90-100 mph (on a relatively deserted freeway, so don't worry), and the response is frighteningly quick. Around one low speed on-ramp turn (30-40 mph), where the car stuck ok but understeered before, it just stuck effortlessly at 40 mph and felt like there was a lot more balanced stick left. Around a freeway transition sweeper (405 South to Slauson, for those in L.A.), the car felt incredibly stable at 100 mph, while before it would have given up at about this speed.
Ride - surprisingly, ride quality hasn't deteriorated all that much. Yes, it's noticeably stiffer, with slightly sharper jolts over larger bumps, but not unpleasant at all. In my view, this is how a street car should feel. [Ed: Bill confirms that Todd's car rides very close to stock and is not harsh at all. For those of you that like a Bentley-type ride for your 996 though, stick to stock - or buy a Bentley!]
Alignment - Where I could only get 1 degree negative camber in the front at stock ride height, I now have 2 degrees negative - the most I'd want to run on the street anyway. The rear is at 1.8 degrees negative. Toe in at the front is just a smidgeon (1/32") in, making for crisper turn-in.
Well, so much for brief! That's it for now. If any of you are thinking about doing this, go for it. Just make sure you have someone who really knows what he's doing do the installation - it's not exactly a bolt-in job."
Costs for JRZ Singles hovver around $2,500-3,000, depending on whether you're getting just the shocks or the other goodies too (springs, sway bars, etc). Doubles, with their remote reservoirs, run about $4,000 +. Add in the cost of installation and things can get costly, so beware! The Penske option is reported to be even better but I have only very limited information on these at present, other than the fact that they are more expensive than the JRZ doubles. By the way, The Racers Group is now the sole importer for JRZ, although Fabspeed and others still re-sell them.
Bill Economos (Chicago) suggests the GT3 street alignment:
Camber: -1.50 degrees +/- .10 degrees
Toe: +08' +/- 05' Total Toe: +16' +/- 10' axle angle: 0' +/- 10'
Caster: +8 degrees +/- 3 degrees
Camber: -1 Degree +/- .10 degrees
Toe: +03' +/- 03' Total Toe: +05' +/1 05'
He adds that for autocross and D.E. he increases the camber: "on the front to -1.75 degree front, which is about as most as you can go with a 996 lowered with H&R springs, and -2.3 degrees back. Also I toed the front out about 1/16 of an inch. This setting makes the ride more harsh, and will probably wear my tries out faster on the insides. So I would not recommend it unless you use your car more for the track and drive quite aggressively."
3. Sway Bars
If you're going to put sway bars in, most agree that adjustability is crucial. Understeer/Oversteer can be dialed in with adjustables but remains fixed with non-adjustables. There are at this time probably only three sources: the factory Supercup bars, TechART, and those produced by The Racer's Group (TRG - Kevin or Erik on 707 935-3999). The Supercups do not fit the 996 properly and extra fabrication needs to be done to the drop links. TRG has addressed this problem with their new kit which is available any time soon. The TechART bars fit properly from the outset and are, apparently, adjustable.