I have never liked the way that the GP's always look like they sag in the rear. A little history: I have a 2001 GP SE that I have owned since new and previously had a 98 GP that I owned since new, both cars sagged in the rear after a relatively short time and miles. The 98 GP actually rode softer than the SE from the beginning and also had the magna steer steering which I did not prefer over the pure R&P steering of the SE which is more precise.
After much research on the rear springs for the GP's, I ran across a couple of forum members that had installed Oldsmobile Intrigue rear springs in the back of their GP's since the Intrigue springs will raise the rear slightly over the GP springs, any of the models-GTP, GT, SE. I purchased a set of 2001 Oldsmobile Intrigue rear springs made by Moog that are variable rate/Cargo springs and all I can say is that I wish that I had done the install previously to now. The car has 120,000 miles on the original SE springs but I changed all the struts at about 65,000 miles with KYB GR-2's which I reused in the rear during the change. The rear raised about 2-2.5 inches with no weight in the car and rides much more solid-not hard, just no porpoiseing over bumps, especially with weight in the rear seats or trunk! The variable rate springs give for the first couple of inches but then become very stiff. With 3 people in the back seat, the rear barely goes down!It now sits like a modern car. The springs are MUCH heavier than the stock springs and have more coils where the spring sits in the strut platform. There is much less lean during cornering and better steering response with these springs. They are great! Bought them from Rockauto for $95 including shipping.
Hope this helps someone!
