Well, that was quick. Nope. Seems that lowering the rears INCREASES oversteer, which kind of makes sense when you think about it. The front will respond quicker and with more control, while the rears get a chance to gain lateral inertia and break traction, causing unpredictable handling.

Okay, that's just my description, but looking around, it seems that I need to do the opposite, and lower the fronts relative to the rears to correct for oversteer. Check some forums and then there's this:

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=58

Mark