Ok, I'm thinking about dropping my ride about 1-1 and half inches all around. I was thinking of using the Eibach spring kit to get the job done, but I have 4 really stupid questions. 1. What is the difference between a progressive and a specific drop? I've only found the progressive drop to fit my car, and I'm wondering what the difference is?. 2. Will I need to install any extra parts other than the springs in order to keep my ride from beating me to death? I hear people saying all the time that with a drop, their ride is really rough. Is that avoidable at all, or just part of the territory? 3. Will wheel well clearance be an issue? I'm working with the factory wheels and rims, so I'm thinking there won't be an issue here..but I'd appreciate input. and 4. Will the car look good with the stock rims still on? I've got the five-spoke stock V6 rims and I don't have the money to upgrade those, if I ever do. Do you think it's going to look tacky, like a car with a bad suspension or should it be ok? I realize I'm asking alot of ?'s and I appreciate any responses to this post very much. I tried to keep it short. 
don't put 20's on the car, you will regret it the rest of your days of owning the wheels when the first little bump you just barely forget to notice, and bam 2 hella bent wheels that are irrepairable. 19's are a huge step, 20's are like jumping off the bridge, don't do it man.
Look at all the Stangs out there with 17s. They look great, and will cost you WAY less than 20s, leaving you with money for other stuff. If you want to be different, I'd say 18s are uncommon enough that you'll stand out. But 19s or 20s are just asking for trouble, IMO.