I'm actually considering nitrous as well. It shouldn't be a problem with the JPJ but insurans I'm not sure. But what the heck, even you change to bigger rims also something it consider major mods and not allowed.
BS,
As for NOS you can actually select your desire nozzle 50HP, 75HP, 100HP. 50HP enought to give you a surge and sprint away. That V6 coupe must have been using the 100HP nozzle without proper mod to suit it. I remember reading one of our local mag review one of the civic in Johor where it is fitted with Nitrous. The editor say it is a nice feeling the surge of NOS.
Ace