Rear shocks

Can someone tell me how much "give" the rear suspension has. Should the rear go down a little if I sit on the rear bumper? My car doesn't go down at all when I sit on the bumper. The PO had the big 22 inch wheels on the car and had even welded ab extension in on the front struts so im concerned that he may have done something to the rear as well.

No - there's too many variables, like how much do you weigh and are your air shocks working...

If I was you, I'd start by looking at a parts guide to see a diagram of the suspension, then I'd put the car on ramps or jackstands, and just have a look.

You could take pics and post them, it's a bit involved but at least it will get rid of any mysteries.

My car's rear suspension is relatively stiff as well. The more important thing to consider is proper ride height in the rear. Proper ride height determines proper tire camber. The rear automatic level control determines ride height. Proper ride height measurements are in the Factory Service Manual.