i'm not holding my breath that it'll work well, but we'll see i guess. there are 2 types - 'normal' and 'hard'. i ordered the hard. the shaft extends as well as contracts. i plan to order a pair of 5955's, and don't want to blow those out very often (even though they'll be much tougher than the 645. at least the 5955 on my eXT8 is tough).
we'll see. it could very well be something that ends up in the toolbox, lol.
i just now got my package from Korea, with the new 'hard type' servo saver linkage. i can barely move it in either direction by hand - so it is pretty tough, or at least much tougher than any other servo saver i've seen. i'll install everything (including the new pair of 5955's and the 17mm adapter/wideners) this weekend.