I just got the car back on the ground today and test drove it with the new shocks on the rear only. I kept telling myself that probably any difference that I would feel would be too subjective to tell. Well, not so. The new shocks made a noticeable difference. I don't think my old shocks were bad. I was just tired of being beaten up by every little bump in the road. I don't notice any difference in handling except for having the 'rough edges' smoothed off of most of the bumps. There is a schrader valve on the bottom of the shocks just like on a car tire where you can adjust the pressure in them. I suppose you could use compressed air, but I would only use dry nitrogen for these. Don't hold me to the numbers because my memory isn't that good, but I think Rob said the shocks come pre-charged with 175 psi dry nitrogen. This is supposed to be the minimum for that type of design. They can be charged up to 250 psi which would probably give a ride as hard as the OEM shocks or worse. The internal spring compressor I bought from NAPA to replace the front springs won't work on the rear springs/shocks since you have to compress the springs externally before the shocks can be removed. I checked around for a source to buy an external spring compressor, and Pep Boys offered to loan me one for free! All I had to do was give them a $50 deposit which I got back when I returned the tool. That was nice of them. :) The compressor comes in two mirror image pieces -- one for the right side of the spring, the other for the left. The problem is that there isn't much room to hook the things up -- let alone trying to have them 180° apart. It took me 3 tries to successfully compress the spring on one side and two tries to get it right on the other side. If you use this method to compress the springs, I highly recommend tightening it with an air-impact wrench like the directions recommend. I thought I would have better control if I did it by hand, but quickly realized that it would take all day. So I got the air-impact wrench out. While I had those springs compressed, I felt like I was holding a cocked and loaded gun to my face. If something slips, there is probably enough force in those springs to take your head off. Also be sure that you have a torque wrench to tighten everything back to specs. Don't let this scare you off from trying it. It's just a matter of following directions in the Delorean Worship Manual. Ahem, excuse me, I mean the Workshop manual. If I had it to do over again, I would look into trying the type of spring compressor that looks like a big duck bill / clothes pin. I think something like that would work easier as long as the shocks don't get in the way. It took me about 3 hours to do the first side and about an hour to do the other side. Practice helps. If you install these shocks, be sure you put the cup & spring on BEFORE you connect and torque the top of the shock body to the car. Unlike the OEM shocks, the 'clamp' that fits on the shock body is a solid ring that won't slip over the bottom of the shock because the schrader valve is in the way. I learned this the hard way. Walt Tampa, FL