I have a 2010 Gary Fisher Cobia and am happy with the bike, but I am looking to put just a little money into some sort of upgrade ($150 or less). What would be the most beneficial upgrade with the limited resources I currently have? Right now it is stock beside a Titec Hellbent stem and Crank Bros. Cobalt 3 flat handlebar. Drivetrain? Seatpost? Thanks for the help!