Suspension ?s

[SOP8920@Siena.edu]

Hey folks,
    As witnessed by a few people on the Kanc run, my rear suspension is shot. 
I would love to go for a Steadi-package, or something like it, but simply can't
afford it.The front struts were replaced about 15K miles ago. The rears, as far as I
know, have NEVER been replaced, the float has gotten to the point where I'm
starting to feel a bit sea-sick.
    I was surfing a bit, and found the Blaufernugen (sp?) page. In it, they
have some interesting options. One is for strut inserts the other is for
complete struts. Will the OEM struts take inserts? Do I need to buy entire new
struts? As far as suspension goes, I consider myself completely ignorant, so
ANY advice would be appreciated. 
                               -Osman Parvez
                                89 200q (149K miles)
                                Siena College
                                Albany NY

p.s. I've noticed a nasty tendency for the rear end to sag when loaded, which
I'm assuming to be the weak struts. However, could this be spring related as
well? Is it a good idea to replace the springs since I'm in there anyway? Would
replacing the rear springs and NOT the fronts have adverse affects? How about
bushings.. since I'm there.. should I have them replaced as well?