I have had the Athena BB Kit for a few thousand miles now. The kit provides a whole new experience, my friend has a stock DRZ400 and I blow his doors off both on and off road. For mods besides the BB Kit, I have the FMF Header/Pipe, K&N Filter with opened up airbox, and the FMF Programmer re-flashed by Doebeck. The Doebeck update solved my minor hickup on mid throttle and minor hot start issue. The Doebeck guys are awesome, if you go with the BB kit, its a must. The included gray box from Athena is Mickey Mouse and requires you to hack into your wiring. Just FYI the Athena Kit says the Piston service life is 15 Hours, this number represents running all out full race. I probably have 75 Hours and my bike runs better now.
Dave