I'm running a stock rear with my Elka's, I plan to buy a new rear sometime just haven't done it yet. I used to have problems with my rear shock but I figured out that the rebound was just set too fast felt like I had a pogo stick back there. I've taken pretty decent jumps since I've gotten it adjusted correctly and haven't had any problems. You can have Elka rebuild your rear incase you didn't know, I think it costs about half as much as simply buying a new shock.