Well I am basically Doing what you are doing...But i have som experience an knowledge...
The reason why people believe that mp3's and nitrous are not good is due to people using dry kits on their mp3's!!!
Most people don't understand that w/ the mp3..it run's leaner than a stock protege or a p5...Why it runs leaner..Simply put the advanced timing!!
Now with a Wet Kit like i am running...You can run a 35 shot w/ little to no problems...Like me!!
But i am pretty sure it's safe to run a larger shot...I am talking to Nitrous Express More about this!!
W/ a P5/protege ecu...You should be able to run upto a 75shot!! Patio has run 14's w/ his p5 w/ only an intake & nitrous!!
Good Luck!!
I will probably go to the junk yard..and pull a protege ecu!! and track days..Go w/ a protege ecu w/ 75 shot..and for street driving...mp3 ecu and 35shot...until i get more info!
Chas