I believe there is three levels of suspension firmness/performance FE1,2,3. You probably have the F3. The main thing that effects ride firmness is the springs. You could replace the springs with ones for the FE1 off a base model Grand Prix, intrigue or maybe Impala from a junkyard. The problem is your ride height probably would be lower with the FE1 springs. Probably not enough to really hurt your alignment though.
You could get springs off a Grand Prix GT or Intrique with FE2 and the ride height would probably be about the same and I think they ride compliant enough. Also while you're in there you could replace the struts with softer ones for the FE2, or get Monroe senstracs. I would just find a Grand Prix GT or Olds Intrique with low miles in the junkyard and take the whole strut/spring assembly and swap it in. Stay way from Impalas though because they seem to have firm springs and floaty srtuts especially the 3.8 models. That's what I would do is get the complete assembly off of an FE2 Grand prix or Intrique. They had similar springs and I think the best ride and handling balamce. I don;t believe aftermarket springs or struts except for maybe Senstrac struts ride all that good or are as quyality as the OE pones. Also you would probably want the rear assemblies too to balance out the ride.
