If it works for you, use it. I think it would be cheating if you were racing friends that lied to you or maybe in you were racing for money and someone lied to you. That is, if you are setting rules or something.
Most of the guys around here are way past that though. Its pretty much "run what ya brung!". If you ask anyone what their car has(that your fixin' to race) your gonna get "stock", "k&n and tb", "gears and exhaust".. Don't bother asking. (don't take it personal either)
If your gonna race, its good to know people. If there is a car I am thinking of running, I start asking around and find out what the car has, lol... I can usually find someone who knows what the car has or what it runs, I know alot of people
As far as 500hp with NA vs NOS vs SC, if its a daily ride I think I'd rather have one of the more efficient power adders that I can drive daily with decent gas mileage and streetability. 500hp in a NA setup isn't real subtle.