I don't know the answer but I can tell you one thing, The G would definately benefit with wider tires on the rear. I tried a few 0-60 runs (with a stopwatch in my hand, highly inaccurate, I know) and when I dropped the cluch at 4k rpms the wheels just spin forever (0-60 in about 7.2). Which brings up a question: is the speedo hooked to the rear wheels in this car? I wouldn't think so but when my tires spin the speedo hit 40 pretty quick and then hovered there for a bit as the tires gained traction, it was wierd.

If I take off at 2.5K rpms the car just lags until the rpms pick up (0-60 in about 8.4).

Then I tried it with VDC ON and it just bogged down and the car lagged like when I took off at low rpms (60 in about 8.5).

All the numbers were VERY disappointing!!!! But I only have 1000 miles on the car right now and I really don't want to over stress the engine too soon by doing a bunch of 60 runs. I think I'll wait a little while longer before I try it again. I think the next time I will also try it at a track with a lot more accurate timing.

Bottom line, I have already decided when I get new tires I will go with 245 ft / 265 rr.

 

I have 1k miles on my car too and you can not launch on the streets at 4k Rpms, that is way too high. I went to the track and launched at around 2.5k Rpms and got just a little chirp and it didn't bog down....granted I only got 2 runs in and I can improve upon my 60' time of 2.28, but in all it wasn't that bad.

You have to feather the gas and have the clutch still slightly pushed until the car grips...and who the Fu*k cares about 0-60 times anyways......all about 1/4mile

 

The speedo is always hooked to the non-driven wheels.

I have practised launching a bit this weekend wit G-tech and went down to 6,1sec for 0-60 and 14,3 for 1/4mi. Had problems with traction as it was -6°C
and road starting to get frosty but on the other side you gain power than as the cold air contains more oxygen. My G is bone stock on 98 octane fuel (premium fuel in Europe).

ChazM is absolutely right about balancing gas and clutch on launch until the car catches grip. If you're launching without any wheel spin the wider tires can make you lag even more.

 

I agree. 2003-04 cobras more rwhp than the 2002-2004 Z06(but the z06 is faster). So i think yes they are underrated in terms of hp to the crank.

 

Keep in mind that magazine times are good for;
1. The particular car they are testing (they can have an abnormally good or bad vehicle).
2. The testing usually does not give you the test conditions (elevation, heat, humidity, track condition).

What this means is the test is good only for that car, on that track, at that time of day, in those conditions. Much different than a manufacturer that tests over a longer period of time and under different conditions.