Not really. The stock servo saver can't really cope with the torque from the Hitec 645mg. I would suggest upgrading to a 'Monster Pirate' steering servo saver. it is pretty much a straight swap for the upright linkage arm. I don't have a link for the part but I do know that the SC store on
www.savage-central.com sell them.
P.S. Once you have done this upgrade you can swap the servo arm for a nice ally one.