At 5 years, and 40K miles your shocks and struts should be fine -- as long as you replaced them with quality parts: Boge/Sachs, Bilstein, etc. (not Gabriel, Monroe or other junk)
Sounds like you need new springs.
On my first brick, I replaced shock/struts at all 4 corners, and was very dissatisfied with the results – still had excessive brake dive in front, and rear was still “Buick-like”. I then installed new springs on all 4 corners, and it was like a new car. In my experience, new springs made a much bigger improvement than new shocks/struts. On my second brick, I did it all at once (new shocks/struts & new springs on all 4 corners) and the car handles and drives remarkably.

Just my 2 cents… arguably worth that.

Jeff Pierce
--
'93 945 Turbo (201K miles), '93 945 (140K miles/I maintain for a family member), '93 945 Turbo (sold w 145K miles), '92 Mercedes 190E (174K miles), '85 Jeep CJ-7 w/ Fisher plow (225K miles), '53 Willys Overland w/ Fisher plow (sold to a loving home)