Intrigue suspension upgrade

Any advice on what I can do / buy to upgrade (tighten, improve handling) my 2002 Intrigue suspension? It wallows all over the place, and has since new. Dealer says nothing available - can only replace with new orig. factory struts. I have installed front & rear strut tower braces but really need stiffer shock inserts, but can't find any after market parts available. I'd rather not go for lowering springs without stiffer shock/struts because the ride may become stiffer, but "pogo" without more damping. Please help!

These guys are primarily 1st generation W body people but some know about or own G2 also. I think pieces from G2 GrandPrix are the same and GP ceratinly had different levels of suspension.

http://w-body.com/forum/index.php

GM dealers are a good place to stay away from, they are all about the cash register, hire new auto school graduates that know nothing about last years models let alone a previous generation of cars, know nothing about cross referencing parts and have no creativity. Most probably dont know a Intrigue is a GrandPrix is a Regal is a Century is a Monty Carlo. They are not car people simply business people. I just cant believe that the Intrigue came with only one suspension level or that suspension parts from GTP or Regal GS or Monty SS wont fit in Intrigue.