During my last road trip, I noticied severe bottoming of the rear end. This was with a full trunk and 4 adults in the car. I had recently replaced all of the struts with Gaberial Pro-Ryders so I figured the OEM springs had seen better days. I had had good luck with Cargo Coils in a couple of other cars I had so I figured I would give them a try in my "95 Olds 88.
I scored a pair on Amazon for $67 and change, shipping was free. I tried using a strut spring tool at first and was unsucessful in compressing the spring far enough to get it out, not much room either. With a floor jack under the rear control arm, I ended up popping the ball joint and adjusting link end with my trusty Harbor Freight pickle forks. I was then able to lower the control arm down far enough to slip the spring out. I compared the cargo coils with the OEM springs and found the cargo coils about a full inch shorter. The diameter of the Cargo Coil spring wire was much bigger than the OEM units. Paying attention to the positioning of the spring ends, I quickly had both of the springs replaced. Lowereing the car, I found it sitting up pretty high. A quick ride around the block and things looked much better. The Cargo Coils raised the rear end about 1-1/2 inches, this difference may have been just the old spring sag and actually may have raised the car to OEM ride heights. A quick drive to my favorite 30mph turn (which I could take at 45 with the old springs) proved a world of difference. The car stayed planted much better than it did with the old springs. Unloaded ride quality did not seem to suffer much from the new springs. The car feels much tighter now. I loaded 'er up for another road trip. A very full trunk and 4 adults again. There was very little rear end sag this time and the loaded ride quality was excellent. High speed passes on less than perfect roads enspired much more confidence. My rear seat passengers also noticed the better ride quality as they were with me on the first trip. I think the Pro-Ryders could use a little more rebound dampning with the new springs but all in all, the spring swap was easy and very much enhanced the handling of the car.