I wanted to introduce myself. My name is Royce, I live in St. Louis, Missouri. I just bought myself a 2001 Hayabusa with 1,800 miles on it and cannot describe how much I love it!!! I'm looking for suggestions for exhaust, (best sound and power gains) what exactly is the airbox mod, and any other suggestions would be appreciated. I already have the T.R.E. and K&N airfilter. I look forward to talking with everyone and thank you in advance for your suggestions.