What problems would i have with corrugated rubber as the ceiling interior of my car?

Nitrous Oxide is dangerous so make sure it is properly hooked up. Also you should never put nitrous on a stock motor, reason being is most factory motors cannot handle the pressure of the nitrous so therefore your risk blowing up your engine. For the material you could try some adhesive material like they use for headliners. I would try the adhesive because its the cheapest.