Too rough a ride. Need advice.

i dont think it is your shocks it is most likely your springs, if you want to change your suspension i would recommened eibach pro kit springs with tokico 5-way adjustable shocks and struts. with those you will get 1.2-1.5 inch drop

yeah any time you lower the car, you're going to get a ride that's not as smooth as stock. A set of adjustable shocks set to the softest setting isn't going to make the ride less hard but will make it more refined if that makes any sense. There will be less up and down during bumpy roads. It will be much tighter but not a harsh tight. Hard to describe but a night and day difference between aftermarket shocks and stock ones.

How much some softer shocks will help will depend on your springs. If you got some real hard-core racing-type fixed-rate springs, new shocks won't make as much a difference than if you had more street-oriented progressive-rate spring. Where your specific Roush springs fall in that range, I don't know. But I think your choice of 5-way Illuminas is the way to go to have the best of both worlds. My car currently has Bilsteins which is a fairly firm shock (similar to Illumina on 4). I love the Bilsteins but my car is part-timed with my wife who does not enjoy the firm ride quite the way I do. I will likely be replacing the Bilsteins with Illuminas to get the best of both worlds ... firm or soft when you want it to be.

Yeah the springs make a big difference on how it's going to ride. Even if several different springs give the same drop, the big difference in handeling is going to be what spring rate they're rated at.

Now, I'm not sure what spring rate roush uses but I would assume that if it's the full stage III, then it ain't got factory shocks and struts.

I'd say look into chassis stiffening as well as other strut/shocks and springs. If you get full length subframes, STB, then the car should shake as violently b/c it will allow the suspension to do it job rather than the body of the car deflecting itself over the bumps. I'd say look into H&R progressive springs with Bilstein HD struts/shocks. Lot's of people claim a good, responsive ride quality. I've ridden in a car with this set up and I'd say it would be more than comfortable for day to day driving on crappy city roads.