when I picked up my 330i sport the bmw store pretty much insisted i buy it. it does make sense though, it was like 499 for 5 years. the insurance is called inTire. it was one of those deals where i had to buy it before i left otherwise they couldn't sell it (obviously, pull out, blow a tire, now can i buy? ha). with these run-flats on 18" wheels i figure it was a good idea. 43k on a car, what's another 500? even covers the wheels. the only exception is curb damage, obviously.
this is the program the bmw store here in cincy sells -
http://www.iasdirect.com/products/intire/