I have had my C4S for about 2 years and have just under 30 K miles on it. I have tracked it twice and have done several AXs. I commute over twisty roads that can be wet in the winter and have limited traction. I am a novice driver compared to many of the greatly experienced drivers on the list.

I think that the C4S handles nicely, and has oodles of traction, but it also displays disconcerting plow and understeer in certain situations. In comparison, the C2 lacks the above tendencies, but has a more flighty and nervous feel to the front end.....IMHO. I have driven several C2s inc. 997 C2, 997 C2S, and 997 GT3, so I think I can compare C2 to C4.

Short Report:

My C4S had a "hybrid street/race" alignment done by TC Design Fab in Milpitas, CA, 1500 or so miles ago. The came highly recommended by several local folks. Tony and Joe support a number of local racers GT3 cars and do many of the Sharkwerks cars. They have alot of experience with AWD turbos as well, which has helped their C4 tweaks.

Here is my impressions after 1500 miles with the new alignment:

The alignment basically eliminated the plow and understeer, and the car has a much more linear and balanced feel. The car can be controllably drifted or agreesively hustled into corners with what seems to be limited PSM intervention. The rear comes around very gradually and controllably under throttle...no plow or understeer, or maybe just a knat's ***........I also note that I fitted Bilstein Damptronics and lowered the car between 1/2 and 3/4 inch. This helped eliminate yaw and the car has a tighter and more precise feel.

With the alignment in particular, the car feels more like a C2 in that the rear end steers more like a C2 as described above. However the car remains quite planted and feels glued to the tarmac more like a C4. It does not have a flighty nervous front end at all - just predictable and linear. I think that I may have found a real world compromise between a C2 and C4 with this set-up, and now have best of both worlds..................Its like having a new car, or at least a new and improved version !

 

Been running 39 psi F and 39 psi R for the last few thousand miles.

Wow, the car handles even more neutral, back-end drifts out out cleanly while on the gas, recovers without fuss..

No understeer.

Very secure in rain this winter so far!

 

Tony and Joe are excellent...they, along with some monoball improvements, new drop links and rear toe arms with adjustment locks transformed the handling of my 996 GT3, which came from the factory out of spec, with loose sway drop links...recommend them for norcal corner balance/alignment