A good nitrous controller can adjust both opening amount and ramp rate. Almost as important as the nitous tune. It works by cycling the on/open rate of the solenoids. You can soften the hit, and ramp in the nitrous so it just adds power without breaking the tires loose. In other words, good traction and tires, ramp in more/faster. Street tires, on the street, slower/slower.
Softening the "hit" also lessens the abuse to the drivetrain/converter.
