I replaced my rear shocks and compressor last year with a package deal from Arnott via ebay...I believe it ran me around $550. Did the work myself. Not too hard but a little time consuming...the upper shock bolts were a pain to see but the compressor took the longest. The 3 bolts that hold the compressor on will break off---no biggie-just drill them out and use a tad bigger self-tapping screw. Also have a vise and big set of adjustable pliers to separate the drier-you get a dryer rebuild kit with the new compressor.
I replaced mine because my compressor was kicking on every 15-20 mins and was loud AF...with the new components-she kicks on at startup and that's it...unless I hook up a trailer or boat.....
Lots of threads with pics and how to's....