As long as you never intend to install long tubes you'll be okay. I know a few guys who have lowered, and then raised their cars back up again simply because they were tired of their headers scraping on everything.
I have the Eibach ProKit and a Maggie catted X and it will scrape. Nice raked look but I have to adjust my driving habits around town. Dropped 1.5" in front and MAYBE .5" in back.
I have Maximum Motorsports coil overs on all four corners. I like them cause you can adjust the ride height to where you like it. They also come with HUGE bilstein shocks. They are a little noisy tho. I had it too low at the begining and I scraped, dragged everywhere I drove. I actually got stuck going into a parking garage....it was like a see-saw! LOL! Anywho, I think my car is dropped about as far as you can take it without those issues. I can't give you numbers right now cause my car is at my shop with the blower off getting ported. But I can measure ride heights on Monday and get back to ya if ya want. I don't think there would be any issues with a non coil over setup except for what U.M. stated. DONT forget the caster/camber plates!
I like the look of yours with the kenny brown springs. Where's the best place to get a set of those? not really looking to improve on anything other than looks. Just want to fill up the fender wells a little better. Thanks for the advice and the pics.