I always thought the saver was a little tight. Before the extended chassis I was running a Hitec HS-5245MG servo, but never had a stripping problem. After the conversion I threw in a Hitec HS-5625MG servo (which looks to be the same as yours on 6v). To be honest though - i've never stripped a servo in my life except for on a crappy Losi mLST.
I think we're just pushing the limit by sticking the truck and 30 series wheels and tires on there instead of the much lighter buggy tires.
Oh well - my amainhobbies order came in today and I have 1- ball-end screws to destroy

before making the next decision on what to try.