Welcome to United Bimmer.
I will agree the run flat tires were a stupid idea. Many owners got rid of them quickly. Im an old school enthusiast and I truly believe the best models they made came out of the 90's. Newest I would go is 2005. In 2006 they and other manufacturers made a switch to intentionally design their cars to be anti-DIY friendly.
I am not a huge fan of the recent introduction of the 4 Series as it is actually longer and wider then the 3 Series, I do think it looks fantastic. My top two picks for current models would be the M6 Grand Coupe and the M5.