His GSX vs your 5m-gte?
If he hasn't done anything with his car you'll win.
The guys around here who have done turbo conversions are doing what.. like high 13's to low 14's on stock boost? not 100% on that so don't quote me.
Stock the turbo eclipses do a 14.9-15.2 1/4 mile.
5m-ge he'll take you by a fairy good margin even if he doesn't know how to drive all that great and you do, unless he's REALLY bad, lol. Otherwise he'd take you by a good 7 cars at least.
6m-gte he'd lose.
6m-ge he'd still win unless he was up against a really good driver and he didn't drive very good, and at that it would be closer but I'd put my money on the GSX.
And like zankone said off the start they're fast. AWD really hooks up.