I run original E39 M5 wheels with oe size 245/40 R18 front and 275/35 R18 rear. Bridgestone Potenza Sport on both axles.
I can't praise these tires enough. The grip is insane! I can floor it in 1st, and there is no wheelspin at all! Even on wet roads!
With other tires, the car has been kind of a burnout machine, but the Potenza Sports tames it. They run pretty wide for a 275, so the outside of the rear tires touch the fender ever so slightly on full suspension compression.
I haven't dared testing the cornering limit of the tires on public roads, but I have tried cornering on the limit of my own bravery, and the tires just grip. Wet roads is no problem either. The tires offer confident handling and gives good feedback. Very stable at all speeds, but on very worn (thanks to people with studded winter tires) asphalt there can be a hint of tramlining. Not as much as expected, considering the sharp shoulders of the tires, and doesn't feel scary.
Comfort is ok. Not great, not bad. A lot of external noise, but the car is pretty quiet inside, except on old rough asphalt.
Sadly they have already started ozone cracking slightly. That's disappointing for a tire in this price range. It's not because of washing chemicals or sun, as the ozone cracks is even apparent on the inside. The tires also get pretty brown, and the only thing I've found that makes them black again is Carpro Perl (water based tire shine, mixed 1:1 with water). The ozone cracks started appearing before I used any tire shine.
Either way, I'm blown away with the performance of these tires. Wear is also very acceptable, with the rears down to 4,8mm on the inside, and 5,5mm on the outside (measured 6,3mm on the inner groove when they were new). The fronts are at around 5,5mm. Pretty good for a heavy and relatively powerful car on grippy sport tires over 3000 enthusiastic miles.
I'm pretty sure I will buy another set of the same tires when they wear out.