The M4 will be an amazing car. But it'll be broadened for en masse. The latest BMW M5 is already exhibiting this. When driving the latest BMW M5, the difference is very small compared to the 550i. The difference between the previous M5 (the E60 chassis) and the 545i/550i models was much more substantial. The E60 M5 was firmer sprung, different suspension system altogether (non active) and had a unique engine and transmission that really differentiated the car. The E60 M5 was a visceral experience. It was a pain in the rear to drive on the road as the clonky transmission didn't like upshifting below 4000 RPMs, and I'm not going to be driving my GRANDMOTHER with upshifting at 4000 RPMs, she'll feel vibrations and even with her hearing aid off, she'll hear the engine. The symphonic engine note from the V10 was nothing short of spectacular, it'd beg to be driven to 6000 RPMs consistently, and it had a generous redline of over 7000 I remember. Driving the car aggressively on an open windy road however proved massively enjoyable and memorable. It was a bit long in length and wheelbase, but it was an amazing machine nonetheless. The latest M5 is just boring compared to the previous E60 M5. However, the latest version is much more usable in chauffeuring the grandmother, the in-laws (if you have those), and whomever you don't want to make a bad impression with.