On 18's, as Flash is, I too can tell about the 1/10 of a difference in my alignment. I just installed some new parts dealing with my suspension and because of the holiday no shops are open for an alignment. Its amazing the difference. My car is a pain to drive how it is now...nearly ran into several people just from hitting bumps.
Any time you remove rubber bushings, you are contributing to harshness and rattles. Its the life of cars. Age also contributes. For me the advantages of solid/delrin bushings over rubber was worth the downsides. The first and formost change for me with harshness was springing. In the end, springing contributes more the harshness than shock stiffness, bushings, or anything else you do. Going from 300/450 to 400/450, to 550/750 now has made considerable differences.
I must say going to the Koni 2812's over the Escort cups is one of the best choices I have ever made; albeit the cost is high. Even without adjusting compression/rebound yet, the car just soaks up bumps much better than the Escorts. I have nearly doubled my stiffness over the entire board, and my new suspension rides better with better control on body roll, better turn in, better everything...and I haven't even gotten it aligned yet. Shock valving too contributes as it controls how HARD you hit the bumps on the street. On the track its different as you don't have pot holes, but a lot of times springing/valving combinations make ride harshness much more noticable.
When I went from rubber to monoball, I felt no difference in ride. There were no added noises, no added discomfort, really nothing. Going from monoballs and camber mounts did not change anything either. When I switched to RE bushings in the rear though, the back vibrated and shuttered a lot more. I 1/3 contribute my hatch seperating from that. Now that I am on lexan its a lot better, but the hard bushings I could definantly feel a difference in the rear.
Wes