I've been looking at the 9xl as well. It looks like you get a lot of bang for your buck with it and most people converting their revos seems to use it.

Since I plan to use the tekno conversion that means I'm using the Revo transmission. What gearing would help me reach those speeds,but still allow me to have good torque. I was thinking of keeping the 2speed intact ,but as far as spur gear and clutchbell goes what are you guys using.

Thanks.