[Devildog2067]

You can use it in 4th, I guess... I never have, since 3rd gear is good to ~80-85 mph...

I don't use NOS in 1st because it's too easy to bump the rev lmiiter in 1st, and that will instantly grenade your engine (supercritical lean = detonation = blown head + holes in pistons + other bad stuff). Besides, it's easier to get a smooth launch by simply revving slightly (I go to about 2.5k, so as not to beat the clutch up TOO much). Launches with lots of power are harder to control.

5th is a bad idea, it's a really tall gear designed for cruising and doesn't take the high hp and torque very well.

2, 3, and 4 are ok... I just don't use it in 4, like I said. 3 at redline is fast enough.