Phat, honestly what you're saying doesn't really make sense from a physics perspective.
Normally for a suspension to "drop" something has to break. The coilover sleeve could coneiveably break, or someone might not have tightened it down enough and the spring seat worked its way down, but for the spring to just compress and stay there is pretty inconcievable.
I don't think that the spring's elastic limit is anywhere within the compression range. (You might be able to stretch the spring into its plastic range, but not while its mounted on a car.)
For the money, the two best combinations in many autocrossers' opinions are the GC coilovers with Koni Yellows, or lower spring rate GC coilovers with KYB AGX's (street, not serious competition).
There are some real performance advanatages to going with matched springs and dampers, like integrated coil over shock systems (Tien, etc.), but there are some REAL cost disadvantages.
Here's what I'd do given my experience. I would find a good Koni dealer (pay the extra $100 for good advice) and ask them what spring rate they would recommend with a set of Koni Yellows for your application. Call until you can get a knowledgable answer from a good speed shop.
Then, call Ground Control, talk to them about the situation - they are also very knowledgable. If they know your goals, they can double-check the spring rates and also advise you on what length springs you should buy and how much drop you should dial in. In the end, you will end up with a matched set of shocks and springs for your application at a much lower price than a full set of coilovers (with an arguably better shock).
If you're serious about performance, then you can corner-weigh your car to get that last little bit out.
If you don't care about performance, just get some Eibach drop springs and the KYB AGX or KYB GR2 shocks. (The GR2 is an AGX set permanetly on the softest setting.)