if you go nitro, forget the traxxas nitro sport. its just not that great. i had one. not nearly as fast as nitro should be. and its a VERY old design. im not sure why traxxas still makes it honestly.

alot of horror stories with nitros envolve 2 things, buying cheap chinese copies OR not following the proper breakin procces.
as far as the cheaper copies, many of them do work fine. but the quality control on these things is poor. so, some people get a decent RC, and others get a bucket of bolts.

what exactly is your budget? you have to consider the whole package with nitros: fuel, glow plugs, glow plug warmer, battery for the glow plug warmer(rechargable is nice) battery for electric starter(unless you get a pull start) charger for said battery, after run oil, a can of compressed air(makes cleaning easier)
so the total for the accesorries can add up.