As I alluded to elsewhere, I had a big day recently for my car. I knew I was going to need new tires before this winter (and before my inspection last week), so a few months ago, I started looking into my options. And the conclusion I came to is the one I could've predicted from the start: dump the run-flat tires, get a good performance all-season through Costco, and have them put them on.
With my last car - the one that got totaled - I did the same (the dumping run-flats part, not the Costco part). I'm guessing that none of you have this dilemma, but several car brands (the ones that still make coupes and sedans) have gone to putting run-flat tires on their cars at the factory. The manufacturers don't like providing a space-saver spare; they don't want their customers driving on them, and they don't like giving up the space for them.
Run-flats allow you to safely get to a place to have the car serviced. But they work by having a much tougher (and more expensive) construction, with really stiff sidewalls. So the ride is much worse, and they cost a lot more. Also, if you get a nail in one, they're really hard to repair.
But every online BMW forum is full of people who recommend getting rid of them. The ride and handling is much improved. And you just need to have a tire kit in your car, with an electric pump and fix-a-flat. So that's what I did. I ordered Michelin Pilot Sports all-seasons from Costco, and had them put them on. About $700 for the set, $20 for tire-pressure monitors and tire disposal, and no charges for shipping, tire removal, mounting, or balancing. Plus they have their own damage warranty.
The car drives infinitely smoother. All the bumps, cracks, and potholes I used to hear and feel, I just hear them (quietly) now. And the handling is still great, probably better. They even had to drill-out my metal tire valve stems (which had corroded), and they didn't charge for the extra labor or valves. I'm a happy Costco customer!