No offence intended but I just bought a 2010 E90 M3 DCT with Competition Package for 110k (incl onroads) so Im hoping to god your completely wrong and the values of the E9Xs stay high.
Understeer is when you hit the wall with the front of the car. Oversteer is when you hit the wall with the rear. Horsepower is how fast you hit the wall. Torque is how far you take the wall with you.