If you swapped your heads yourself, you'll be able to install a Zex kit. It's pretty straight forward. A lager fuel pump would be a very good idea, and an AFP wouldn't hurt either. Get a bottle heater to keep the pressure up, a gauge to moniter the pressure. A new kit from Summit is around $500. Gauges run anywhere from $50+ depending on which one you get. Oh yeah, get a purge kit too. About $100. Heaters vary, I just ordered one that is pressure controlled, about $170. That should be all you need, minus the nitrous itself. With any power adder, you have to be aware that your motor could go anytime, but running a Zex kit 'safely' you should be fine for awhile. I would start out at a 75 shot and not get too greedy, maybe 100 after a bit of time, but I would shy away from the 125 for quite some time. Premium gas is definately a requirement also (92+).