My STi is fully stock with the exception of a cut off air box. My friend's 350z has a Catback dual piping exhaust system, Intake, and Air/Fuel Ratio controller (may have more mods though).
We were at a 25mph roll, i was in second gear, 3 beeps, we take off, i get a head start, to my surprise he kept up. I underestimated the 350z, I thought it would be an easy win.
Through 2nd and 3rd, the front of his car was parallel to my rear wheels. (Forgot to hit my IC Spray!!!!)
Hit 4th, a very small gain (I think the front of his car was now parallel or slightly behind my rear bumper), but he was still there. At the end of 4th gear, he kept his ground.
I'm pretty happy with the results.