i'm trying to get a used kit for my friends 91 lx 5.0, there is a zex kit on ebay for cheap. It has the nitrous management unit, i'm not real up on that. I have a NX kit. Does this thing only let u spray at certain rpm points, or do i need to get a window switch for him??? I'm jst gonna slap on a basic kit, but i don;t want him to blow up. 75 shot ZEX, with window switch(a must IMO if the kit doesn't have it). He can risk it with the stock plugs, no FPSS, and no purge, with a 75 shot and he's cheap, i'm doing ghetto speed for him. Thanks.