I had this issue back in the late 80's when I had an Rx7 turbo, which came with a suspension that was masochistic on its best day. It got to the point where I dreaded driving it, every bump or crack in the pavement was like getting smacked on the bottom and every panel and piece of trim creaked and rattled on anything but the smoothest roads. Why any car would need a suspension that stiff was beyond my comprehension. I had non-turbo versions before this one and they were nothing like that and they handled great. I ended up diving through the various local junkyards and found a wrecked non-turbo base model and grabbed all four struts.
At first I paired the base model shocks on the turbo springs and tried that out, but not only was it still too stiff but the base model shocks couldnt control the turbo model springs, so I got the horrifically firm ride coupled with too much float. Then I put the base model springs on the turbo shocks, and that was the ticket. It completely transformed the car into a firm and sporty, but very pleasant ride and I drove it like that for years until the engine died. Honestly if I hadnt found the base model springs in the junkyard I probably would have gotten rid of the car because it was just way too stiff for my tastes.
I would add, dont overlook the sway bars as well. I went to a smaller diameter bar and that made a very noticeable difference too, the handling and lean in corners didnt really change much, or not enough to justify the larger bar and the firmness it added, but it definitely helped the ride quality on bumpy roads.
So swapping out sway bars and springs and nothing else transformed a car that I thought would go down as one of my biggest regretful automotive purchases, into a car I couldnt wait to drive.
