Be sure and have a look at the DOC.
Make sure the crank float is correct.
Make sure you have the timing set correctly, you will have to use a strobe.
Make sure that your jetting is spot on.
Have SPARKS rewind your stock SEM ignition so it will last, and provide spark that will be consistent, strong, and won't get snuffed out at high rpm's and WOT.
As far as exhaust goes, just get a slip on that will allow the motor to breathe, the stock one is trick looking and super quiet, but very restrictive. This one mod will really wake that bike up.