i am thinking about hooking up zex to my 99 si after i replace the internals and pistons. i just wanted to get some feeback on the kit before i figure out what im gonna do.

 

Zex makes a good kit. They are relatively inexpensive and easy to hook up and use. The Zex kit I have is set up to use wide open throttle activation so that the nitrous will only spray at WOT when the system has been engaged (instead of a push button activation system). Get colder plugs and use 92+ octane fuel and you should be ok up to a 75 shot. A window switch is a necessity so that you can set your nitrous system up to shut off at an rpm level before you hit fuel cut. Fuel cut + nitrous will lead to a blown motor. A bottle heater is a great investment to keep your bottle at the optimal pressure level. Good luck