As far as I know...you don't. NOS is used at higher RPM's as an intense burst of highly flammable liquid to blow your car forward. To use it in lower gears, at lower RPM's (like during turbo lag) would be pointless. You would max out the gear faster than you could shift. Not only that, NOS is used (I'm pretty sure...someone correct me if I'm wrong) primarily for street racing. I don't think a commercial car company would mass produce an expensive street racing mod like NOS into all their cars.