My best friend has a 99 Z24. With intake and exhaust only it runs 15.7. Seeing as how some members with SVT's have had trouble just getting to the 15's, it's very possible to say it's a drivers race.
I've run his Z24 a few times at the track. I can get a 2.1 60' consistantly. Something i can't get out of my SVT.
But, stock vs stock + equal drivers = SVT is faster.