Yes some late model 99's and most 00 model contours have the returnless fuel system. (this will become standard on all new vehicles in the future - more reliable and easier to control via computer)
You would need a wet nitrous system. (adds both fuel & nitrous)
IMO I would not make your decision on what year SVT to buy just based on a cheap nitrous system...
That's like saying I want to buy a Fiesta because I can re-use my 13" tires and wheel covers...