Hey LOAF,
Of course the state is gonna give you thier easiest answer - "It has to be stock motor with no mods, blah blah blah". In my area (Norhtern VA) we have the rolling road emissions test as well and if you ask, they'll tell you everything has to be bone stock. However, they never actually have to document any of the visual inspection, the Dept. of Motor Vehicles only wants to see the actual numbers. The same may go for NJ so you should ask around any of the classic car crowd (VW, Chevy, etc.). Maybe jump on the
Shoptalk Forums.com and post to see if any from NJ has gotten through emissions inspections and see what they say.
Brian