mucusmembranesmoist wrote sucks that there is no run flats....
I used to think they were the best compromise... until I dug deeper. Not anymore. First of all, you need special equipment to mount/dismount them, and you're not going to find that in any small city or town. Second, and more importantly, they're not supposed to be patched, and no shop with the proper equipment will do that. Third, NOBODY will carry those sizes, so you'd be stranded for days. And fourth, and most importantly, the tire will completely collapse after 100 miles or so (depending on weight of the car), so hardly the 'piece of mind' you want.
I just found out the best solution to the flat tire issue: carry a jack and the 'Stop'n Go' flat tire repair kit. AND avoid any construcion zone or rolling on questionable surfaces, and you can pretty much avoid having a flat in the first place. I tried my 10-yr-old patch kit the other day, and after learning how to properly plug the tire, took the safe route to not exceed 80 sustained, and traveled 320 miles like if I didn't have a flat, and with the piece of mind of TPMS and the same load range as the other tires. Glad I didn't buy a donut spare, because I wouldn't carry it now (I don't trust them on the highway, and wouldn't exceed 60). Your call, but I'll NEVER consider runflats again. Take care.