You can limit the throttle epa which is basically the same thing as putting a restricter in the carb. Just run it down the straight and keep setting it lower until it's not stupidly fast or out of control and that should make it better everywhere else as well. I do this on my brushless T4 and it works well. On my gas trucks I usually just tune them a little fat to tame them down depending on the track surface and layout. You can change the gearing to tame it down as well. Lots of different ways besides buying a new engine. But since you have one on the way that's the easiest : ) CV-R is a great engine.