I've been real happy with this one from Todd.
I purchased the cheap prototype with non-removable DB killer that I'm very happy with. The bike probably lost 25 lbs
now for the ownerYou will have to update your ECU though which you can with the $300 or so you'll save over most other brands.
The only problem I had putting it on my old griso was the connector pipe was not round. I tried various methods then just used a muffler clamp to make the tube round ahead of the muffler, slipped the muffler on easily and removed the clamp.