At 24K mi one of my Pirelli run-flats developed a side bulge.
I am finding out that run flats are sensitive to impact (potholes, brushing up agains a curb) so this is apparently fairly common.
They have some sort of pro-rated road hazard warranty on them, but I am not even going to bother.
Consider, if something like this happens, you will likely have to replace 2 tires (to avoid running on 2 differently worn tires) and of course the other undamaged tire would not be covered by warranty. BTW good luck trying to get a tire shop plugging run-flats should you pick up a nail.
I am opting to ditch these evil suckers. For the price of a pair of the pirelli run flats, I can put on a full set of Michelin non-run flats.
MB in their infinite, er.. wisdom did not provide enough storage space for even a donut spare.
I could forgive them not providing me a spare, but not providing the place to store one should I want one, is inexcusable. The user's manual suggestion to use tire goop on non-run flats is utterly lame. The goop ruins the TPM, and makes it impossible to plug the tire.
I think I will just carry a plug kit so I can plug any nail holes if one should happen, right then and there.