you can run a 75 shot on a completely stock car. if you go higher, get a tune from brenspeed or equivalent which will adjust your timing and a/f ratio accordingly as well as all other parameters that are improved with a tune. do you not already have a CAI/tuner combo??? you should get that and when they send you the tune, just retard the timing a couple degrees and run the nitrous. trust me, cant go wrong with it...