If you lower a BMW too far, the front control arms get pointed the wrong way and the camber curve inverts. This means, as the car leans into a turn, the outer wheel goes to positive camber, which reduces front grip. Look under the front of the car with it sitting normally, the front lower control arms should tilt downwards from the center of the car to the wheels. If they are level or pointed up, the car will handle VERY strangely.
Also, BMW suspensions tune differently than others. To reduce understeer, you INCREASE front roll stiffness. This is because there is not enough camber gain to offset the body roll. So you reduce body roll. If a previous owner did not realize this, they may have tried removing the front sway bar entirely to "reduce understeer."
Then finally, you need to check the front lower control arm bushings where the control arms attach to the chassis at the rear of wheel well. If they are worn or soft, you can get a darty feel.
And finally, check the alignment. Some track people set up cars with toe OUT in the front to enhance turn in.
'95 Alpine M3 LTW
'00 Dakar M Roadster
'02 Topaz M3
Red/White SRF #4 (Chassis 561)