No matter what, whenever you lower a car you need to get aligned back to factory specs. We (Eibach) recommend an alignment kit if it's more than a 1.5 inch drop. Hope this helps in your decision.
I just got my eibach pro kit installed with BBK cc plates, a fresh alignment, and a complete front brake job with new rotors/pads. Handels and drives like a new car. The new rotors look nice through the 03 cobras also.
I suggest getting the cc plates, with the springs and aligning her all at once. If your gonna do it, wait untill you can do it all at once, and do it right. You'll be glad you did.
if you want to do it right, look forward to spending some cash if you go lower than 1.5". than again, if you have the money to spend for around 1300 you can get what I got. but you will have to replace balljoints, bumpsteer, at some point. click my cardomain link, and let me know what you think. chris