I went through so Many headaches w/ learning how to set up digital servos...I tried these
hi-tec:645MG / 5945mg / 5645m.... great analog servo but I had 2 bad digitals right out of the box in a row...the first one I killed myself so I cna't blame them.
Then I found my true loves
JR 8611 for steering
Tank of a servo never failed me in 5 months of serious abuse
and
Futaba 9451 for throttle...same thing never failed me yet...thought I had one go but it was my Tx.....just read A LOT before installing digital servos...all your linkages have to be set up perfect or you will be cooking anything you use.....digitals are great cause you can use better radios and take advantage of the faster Tx/Rx rates....