I've used rayaracing and he does great work. Os rocket is also good, but if it were up to me, I'd go with ray. He would be my choice. Again, both do a great service to racers and bashers by allowing us to extend the life of the motors we buy. Before this type of service came out, you really had a hard choice to make whether to rebuild or buy a new motor. Now it's alot easier to justify spending 300-400 on a motor cause you can always get the sleeve pinched once the compression is gone.