Well either way you decide to go your internals might not hold up. With nitrous it all depends on the ch!t you want to put on it, too big a shot and you can kiss your head gaskets goodbye. Supercharger is the same, plus if your going to supercharge your gonna have to compensate for more air...
brules fun when its not busy, long island is good to. vega is pretty good when you get off the main pipeline, thats where we usually ride, slave lake/smith areas fun too
also a 125 will teach you to ride faster and better bike control then if you just jump straight to a 250f. you have to be on the pipe to go fast. i find i get lazy with my 250 2 stroke all the time. but just my opinion.