Joe, you are a young guy at 21. The future is in water cooling, electronic fuel injection, computerized engine management, etc. My advice is to start out with as modern a bike as you can afford. Do not dump a lot of money into it. Simply learn how all of the systems work, data collection, EFI and ignition chip programming, modern chassis setup, intake and exhaust tuning, how to ride, traction control, streamlining, etc. All of these skills need to be mastered to be competitive during your career. The sooner you get started the better you will be.