Folks, since I had the FIRST nitrous powered Marauder (on and running at Marauderville I, Sept 2003), and I used the very same kit(klmore got it from someone else that bought it from me, but was threatened with divorce if he didn't get rid of it). I can, in good faith, tell you that, if properly installed (which is quite simple, and takes only a couple hours), a shot up to 125 hp will not require modification of the tune, since the EEC V adapts all timing retards automatically, and the nitrous application will not hurt your hypereutectic pistons or stock rods. ANYTHING above that requires a professional tune from Superchips or Diablo (I recommend Superchips). You can make up to 425 hp safely with the ZEX. It's more than most people really want in a street machine. I opted to upgrade to an NOS NOSZle system, which is direct through the injector ports. It is designed to handle applications up to 1000 hp or more, of course, with the proper motor. This is a good deal! The group buy will save you $160 bucks off what I paid for it back in 2003. But, beware.......this upgrade may not be enough for you, as Pat has discovered. You just might want MORE!