I've recently been doing a lot of research here, and else where on this exact subject.
The first thing I would say, and this is more from a common sense point of view then a factual view, is that I think it would be really really bad to have aftermarket springs in the front and stock springs in the back. I know plenty of people run different spring rates front to back, but I think those are on more custom vehicles and I think the springs and rates were carefully selected for a dialed in competition setup.
With that said, I have discovered that Tein makes a set of s-tech springs for the wagon that drops the front 1.7 and the rear .5. Tein has a picture of a white wagon on their site with I think 17" wheels and those springs level the wheel well gaps quite nicely, while at the same time maintaining the consistency of a matched set of springs at all four corners.
I have also learned through my research that most aftermarket spring kits are stiffer than stock to varying degrees. Since the stock strut rebound and dampening settings are matched to the stock spring rates, if you put stiffer springs on, you instantly have struts that are underdampened, and my guess is that the car will bounce a lot on the street, and you'll wear out the stock struts really quickly. I see lowered cars all the time that bounce really bad, and I always wondered why. Now I know: stiffer aftermarket springs with stock struts.
With all of *that* said, I am currently investigating the possibility of either
a) buying KYB AGX adjustable struts and modifying them for my wagon (they were designed for the sedan which has a wider track, so the bolt holes need to be tweaked to maintain stock camber settings)
b) buying the Koni inserts, dismantling my stock strut housings, and adding the inserts. This way I know without a doubt that I will be able to dial in stock camber settings, but still have adjustable dampening to match the new springs and my driving style.
I am going the strut/spring route instead of the coil-over route because I want an agressive street setup, not a track setup.
If anyone else wants to confirm or deny my findings, please comment.