Ground Controls are good - they use Eibach springs. The only problem is they use your existing struts, which is okay if you don't plan on lowering the car that much. But if you lower it more than the strut was designed for, you'll end up hitting the bump stops often, and the strut tends to not do its job as well. From what I've seen, they're best used with Koni's, since the Koni's travel is shorter than some other struts available.

If you go with Ground Control or another perch-only-type kit, you should definitely consider getting some Koni's - which may put you in the same range as an entry level "true" coilover kit from Tein. Otherwise, just go with some lowering springs until you have the money for a true coilover setup and save yourself the headache.