Don't get the JRZ650 servo, they don't last, I ran them on my buggy's and truggies and they give out quickly. Any high end servo of any brand works fine just stay away from the ACE servos some are good but some are also bad and have 0" warranty.

I currently run the JR 8800t and 9100s and even the 4800t which is non digital and all work flawless.