Really, I've never seen a single lap time from a C4S that's quicker than a C2S. Same engine but much heavier, so it's slower. Please, in all seriousness, point me to the data comparisons showing quicker lap times for the AWD car. Curious, none of the top-performing Porsches are AWD (GT3, GT3 RS, GT2, Carrera GT, GT3 Cup, RSR, etc.).

Out of curiosity I just looked up the Nurbergring lap times.
Autobild, 2009 C2S PDK, 7.50 minutes
Autobild, 2009 C4S PDK, 8.05 minutes

 

Here is a nice comparison, even though it is in Japanese, you will see that the C4S is even with the C2S in 1/4 mile times even with its 60Kg weight disadvantage.

http://www.youtube.com/watch?v=I1gb26rsFHE

 

GT3's, GT3rs, GT2's, etc... all have a lot more horsepower than a C4s or C2s and would be expected to have better lap times. A 911 Turbo, a 4wd car, has shown better lap times than a GT3 and GT3 rs:

http://en.wikipedia.org/wiki/Nürburgring_lap_times

 

To the original question of C4S vs. C2S, I just went through the same comparison.
Since I don't track my car, and it's a daily driver, I just based it on the feel of the car, nothing scientific.
I drove the C4S first, then the C2S.
BINGO--I bought the C2S, it was more like riding a horse that's a bit wild, vs. one that's a little more poised but just a bit duller.

 

Grip and handling are very important to the way a car performs on the track. It is not just about horsepower and weight. Lets not forget what a GTR can do on the track.

 

Here is a recent comparison from EVO magazine where you will see that the C4s is about a second quicker around the course:

http://www.evo.co.uk/videos/trackday...rack_test.html

 

Ah, it was raining on that track
And the track that they test on in japan is more like a carting track. Seems like they also manage to make 350Zs and NSKs go inordinately fast on that track too! But, if you note the lap times when they did the multiple porsche vehicles, the fastest single lap was the C2S......

The reason why porsche makes the GT3 RWD is telling. Same thing for the GT and the GT2! All the performance porsche models are RWD. If they put an AWD system like the GTR in it, well that would be a different story.
My take is that 99% of folks wouldn't notice the difference between the C4 and C2, so go for the good deal. They are both superlative cars!

 

I can see how a C2S and C4S with street tires that are cold could have similar lap times. The benefit of the C4S traction will make up for the lack of traction of the C2S on cold street tires. However, as soon as you have tires that are warmed up (and assuming the track isn't wet/damp), there is no way a C4S can be faster. When the tires are warmed up for both cars, grip is equal. It is only once grip is lost, that traction plays to get the car back to optimal grip (given the conditions).

We know from track work, that as soon as you start loosing grip (tires squealing), it is likely becuase you are over-driving the tires/line/conditions/car.

Cheers,

Jason.

 

I'm definitely on the rear wheel drive team. It's more challenging and rewarding.

To be fair though, the 918 concept is AWD.

 

The c2 folks are going to say get the c2 and the c4 owners will do the same. Just get what you like/need. Both are great cars. You won't regret it.

 

I drove a C4S Gen-II for the first time a few days ago. It felt vague, 'understeery' (is that a word?) and under-damped. I didn't like the experience at all - it gave me no confidence through fast corners and little feedback to let me know what was going on. This may be because I was mentally comparing it to my current Gen-I that has Damptronics and a really good setup (making it a lot sharper and more responsive) whereas the Gen-II C4S was bone stock. Then again it may be that the C4S just lacks feel compared to a C2. Not sure.

I do remember finding my old 996 C2 to be much more communicative than the C4 that preceded it though - maybe the trait continues?