As far as paring these up with Sleeve-Type Coilovers. i.e Ground Controls : There is a limit on the Spring rates that the AGX's can handle on compression and rebound, Max is 300 in/lbs, anything after that and the shocks/struts will deteriorate quicker than their normal lifespan.
I Love the AGX's Good bang for the Buck, i have these on both my Nissan's which includes my SE-R track car w/ a 300/200 in/lb Ground Control Coilovers, adjusting is very easy, fronts are w/ the supplied flathead screwdriver and the rears are just a turn of the knob.
For the price, they're great! and its about $500 for the WRX, but still great.
I have the GC8 ones, so maybe the not so great ride over small bumps has something to do with it being on the wrong car. However, I am curious as to how a 4-way adjustable would be for fine tuning, because I got used to the 8-way on the GC rear struts and even with 8-way adjustment, I need more...