Down here in Australia we had the same problem, massive steering but couldn't make the rear end go with it....we couldn't find that "nice" balance...

What we did was to use the lower roll center pin position in the front end - totally transforms the car.

Just a small note re. the springs , the aqua springs and the sock springs have the same wire thickness, but the stock springs have 1 extra coil ( which makes them more progressive ) - as a starting point, try aqua fronts and stock rears