here's my take on nitrous:

it's not cheating at all, in racing u give wutever u got to go faster.. if nitrous is cheating, then so is turbo, SC, gutting, Modding in general

however, i don't like the idea of people just getting nitrous on a relatively stock car and using that as the main power adder b/c it's only temporary.. it'd be lame to hear someone say "nah i can't race u today cuz i ran out of nitrous".. a real car shouldn't rely on the bottle.. turbo/SC is different, it doesn't run out

on the other hand, if you have some form of FI and really beefed up internals then i think it's okay to have nitrous just b/c ur not exactly relying on it, it's only helping u and ur car's still fast w/o it