From the NOS Website
Nitrous Progressive Controller (which can essentially alleviate the problem with breaking something due to instant torque, the main disadvantage folks say nitrous has over T/C S/C....not an issue if you use this), see below:
"A major concern of any racer is being able to "hook up" for optimum performance. This is especially true of cars equipped with nitrous systems, as applying hundreds of extra horsepower can often over-power the traction available with a given chassis, tire and track condition. Through applying nitrous gradually, or in stages, it is possible to give the car as much power as it can handle at any point on the track. Extensive testing has proven the use of NOS controllers to dramatically lower elapsed times in many applications.
Programmable Progressive Nitrous Controller
This top-of-the-line unit can be programmed to control both the amount of nitrous that is flowed to the engine (from 0-100%) and the time desired to "ramp up" from first hit to full flow. For example, you can program the controller to flow 25% of the nitrous 1.5 seconds into the run and increase it to 75% nitrous at 5.3 seconds. Or, it can go all the way to 100% much sooner. This enables a racer to "fine tune" the power curve of an engine to best utilize prevailing conditions. It can also be used to activate a retard box or 2nd stage of nitrous. Clearly, this is the most sophisticated progressive nitrous controller available today. However, it is very easy to use, and each function is set through simply turning a series of dials to the desired position and pushing a "program" button.
NOTE: All NOS controllers are safe to use with any NOS solenoids. Other manufacturer's may have excessive draw. Nitrous solenoids should not exceed 10 amps; fuel soleniods should not exceed 5 amps."