I purchased a 35i BMW Z4 from a family member, it was fitted with Bridgestone Potenza run flat tyres, new ones at the rear and well worn at the front. The car tramlined constantly, grip was poor at the front and lane changing was unbelievably scary. I took the decision to fit the latest Goodyear Asymmetric 5 tyres all round and the transformation is unreal, I did also have a 4 wheel alignment performed but it was largely fine and the worst mis-alignment was 0.21 degrees so I do not think that has contributed to the change. The car is now stable and calm, there is zero tramlining, bumps do nothing to upset the car, changing lanes is now a joy. Cabin noise levels are also significantly lower. Wet grip is impressive and in 400 miles of driving, much of it on wet roads, I have not managed to provoke the traction light even pulling out of junctions and being spirited. By contrast the Bridgestone tyres shocked me by flashing the traction light in the dry on a bend I regularly sailed round at the same speed in a 54 year old sports car!
To sum up, the run flat Bridgestone Potensa tyres were horrible and dangerous and the Goodyear Asymmetric 5 have given me the car I expected, the difference is total. Z4 owners buy them and change your life!!!