Are you happy with how it handles ? If not there are some fairly cheap mods to help fix that. Camber shims, flipping steering horns to help bring down bump steer, aftermarket axle, from time to time there are used front works shocks or yfz 450 front shocks.
Power department could be very simple things to start it off, make sure your airbox lid is off, better pipe, bigger carb, depending on how much money you wanna spend you could get it ported and head cut.
Lots of options you need to figure out what you would like to improve and how much you can spend. That's a HELLUVA deal for $150!! Your very lucky to get that!