I'm still driving up to 9/10ths and I hardly notice a difference between my summer and winter setups (considering conditions). Michelin PA4 is where it's at! I'm at 23700 miles now and my paint is virtually flawless and I park outside every day too. I came from a WRX and compared to that, BMW paint is like mithril lol.
My leather is a slightly different story though. The driver's seat is more stretched than I would like and it's a little shiny but this improved some after I cleaned it last week. There is no wearing through the leather though which I have been worried about because it's so delicate. My only real issue is that I'm 90% sure I have a broken motor mount and I have an appointment with BMW Seattle on Friday. Previously had an EDC module go out and the whole unit was replaced.
Overall I'm feeling good about the health of my bimmer and hope I can stay satisfied with it for at least another 5 years.