There are a lot of options, and some of them come down to personal preference. Personally, I like Aftermarket Assassins. They have more options for the clutch kit than most the others. Like the Buttershift Washers and billet primary cover plate.
I’m running the Gilomen ECU tune, and I’ve swapped in an ECU with the Aftermarket Assassins tune, and can’t feel any difference between the 2.
Both Gilomen and Aftermarket Assassins are great to work with, and have awesome customer service.
Evolution Powersports is another solid brand, but they have a more conservative approach to tuning. They won’t remove the seatbelt or start in gear limiters.