For my Hawk, I've piped and jetted it and made a custom air filter. When I put this bike together K&N wasn't making a filter for it. So I took the stock airfilter, cut out the paper medium and replaced it with airfilter foam, sprayed it with some K&N oil and away I went. (K & N now makes a hi-flow filter for this bike)

I've also got a Two Brothers exhaust for this bike and it rocks. Smooth power delivery, and it sounds great.

I'll add some more pics soon.