M3iRiSH

Maybe you picked out a slow S... ; )

Cup-a-Chow

I can pretty much guarantee you that an LS1 would rock you pretty damn hard, especially on the freeway. I ran my 98 LS1 auto bone stock and ran a 13.43 with a 2.13 sixty foot, while the S4 ran a 13.49 with a 1.78 sixty foot. The S4 is all launch and the Z is all power. Especially on the freeway, you wouldn't have fared that great.
And we're talking about a stock Z compared to a chipped S4... Throw a torque converter in an automatic and say hello to 12.8x's