I have a 96'LS with intake, intake manifold, catback, and im running a 100 shot of nitrous...my car is idleing a lil high..ive checked multiple times and had other people check for vacume leaks and cant find any...i tested the TPS and the voltage that i got when the throttle was closed was .72v, i know that the tps is supposed to read .5v..would that much of a difference make my car idle at about 1500 rmp?

 

At idle the TPS should be between .2 and 1.4v, at WOT it should be 4.8v, when you move the throttle slowly the voltage should go up smoothly and evenly, you could check to see if it's doing that, but by what you listed and are describing it seems ok.

You could also try unplugging your IAC valve and see if the idle drops to around 500rpms or so, if it does then replace your IAC valve, if it doesn't, that's not your problem.