Thanks for the clarification; I did indeed think that you were talking about a front fork. The only suggestion that I can make is to make sure that the compression/travel is the same on any fork that you are looking at.

I'm assuming that you are buying an older shock online, so I'm not sure that it is any better deal than rebuilding your current shock. At least with having someone repair the existing shock, you'd have some sense of support if anything should happen. Again, perhaps you should ask your LBS if in their opinion if would make more sense to buy or rebuild.... they may know/see things about your current shock that we here in online world do not.

Again, good luck!