The only two that I know about are Vari-Flow and Dial-a-Jet. I installed Vari-Flow this summer, and have used it once this year and loved it. However, I've got carbs, not EFI. Any EFI I've seen don't need either of these devices. I've got Pyros to monitor EGT's. I'd love to install a RacePak, but it all costs money. What range of elevations are you riding at?