$ 180.00 is alot of money just for parts. I got mine from Phil and if I remember they were less than that.
It`s any easy job, Make sure to replace the fluid with MB fluid. After your done, put 250 lb`s in the trunk[ 2 or 3 friends} , start the car and run at 1500 rpms or more and the car should raise to the proper ride height. Put the weight in the trunk before starting the car. Also you can drain the old fluid at the valve near the rear axle, it has a bleeder.