I would probably go for 4s and 3 k sounds good but extend it a bit more too like 6250 or 6300rpm. 2nd gear is a debatable one to be honest. In some cars it's fine but with the vr6 gearbox second isn't as amazing strong. Especially when your smashing 150 extra through it. Third is the best gear to start nitrous with. As for the road legal aspect, I'm 80% sure that it's fine to have it in your car all the time, fine to have it all set up etc as long as it safe, but the bottle must not be opened when on the road. As it means you have been using it and they know if you've been using it then you ha