You can rebuild it or have Jerry Hall rebuild it.  He'll re-valve it, new spring, it's a pretty good set up when he's done.

As for the fronts you can run a banshee shock in the stock set up and some people run the YFZ450 shock but they are technically too long and there is rumor that it can push out the ball joints so if you do this make sure you put new BJs in when you put the new shocks on.