It is mainly the run flats switch to non run flat and you will not have that skipping over the pavement feeling. I was once driving a 645i with run flat 19" at close to 136 mph taking this kink and all of a sudden the car hit this bump in the road and the 6er nearly jumped above the pavement for a good second or two and landed in the middle of both lanes. Thank god it was an empty highway because it was scary. Unlike the normal tires the run flats do not soak in the bumps but rather just skip over them.
On the other side recently one of my friends was involved in a serious wreck with his E60 M5. He had replaced his run flats with non run flats. The car was doing over 150 mph plus when the rear tire busted and the car lost control went into a ditch and hit a small fence and flipped over multiple times. This resulting in serious injuries to all the occupants of the car. The run flats have a good and a bad side. If maybe he had his run flats they would not have just blown out and he would not have lost control.
Another thing is that 335i has lot more torque at a lot lower rpm with no LSD but from all accounts the non LSD 335i coupe ran faster in Car and driver on a race track compared to many LSD equipped sports cars including the in house BMW Z4 M roadster etc.
here is a pic of his beautiful M5 all torn to pieces.