I was having basically the same problem with my coilovers when I got them.. I had them set to the lowest setting all around.. Car would plow, then snap to oversteer..
I raised the front setting way up to help turn in, and kept the rear fairly low to help with tail getting happy.
My settings are now 11F 2R dry.. usually about 13F 2or1R wet..
I usually play more with tire pressures to fine tune the car..
I also agree with Movinup.. Fix those Bushings NOW.
