My brother just traded his '99 Z 6-speed for an '02 WS-6 TA last night. We were goofing around a little on the way.....
His car has a lid, SLP exhaust, Z06 clutch, and some other mods. First time we left a light with me behind him. I stayed glued to his bumper and had to pedal it to keep from hitting him.
2nd time, I was in front and he stayed glued to MY bumper while I spun half way through 2nd gear (broke loose on the 1-2).
I'm in "street" tune with conservative timing and 17-18 PSI. I was impressed with the way the LS1s run, though. The Z ran a 13.4 @ 105 totally stock. We're hoping once the WS-6 is broken in it'll run a little quicker (some folks are saying the '02s are a little quicker).
Bottom line is you have to have a little more than the basic mods (mid-13 sec range) if you expect to walk away from even a stock one.
Jim