Muggs I have the EFI on my K-9 and i love it fixin to go to durango colorado next month which is 8 hour drive will go threw couple of passes my wife and i planned on going to higher alltitude and hope the map sensor will help it run better in higher elevation as far as the sound it sounds the same as carbs throttle response is the same. it cost 2K more to get EFI but i plan on going to the mountains alot and didn't want to worry about having to rejet bike