your on a great track man! first deff. get those internals in. next what you do is sell your mp3 ecu, you will get like 300 bucks for it and be sold quickly. buy a p5 ecu, then buy the splitsecond piggyback from protege garage that sells for about $570.00. this will allow you to tune air fuel ratios and retard your timming.
the piggyback,forged internals, cold ass spark plugs and freeing up the motor with a full exhaust and full intake ( including the 626 manifold) would say,you would have a fast ass protege that runs nitrous.
btw- make sure the nitrous is set at wot, that will elimate alot of the problems that people have with nitrous.
another note, wet kits distribute the nos evenly comparted to dry kits. a 50 to 75 shot of nos from a wet kit should be safe, keep us posted man, and maybe make a custom thread about this!!!!