The CPO on my 2011 550i is expiring soon (due to time but almost at 100k anyhow). I was able to find a Route 66 Main Street warranty that will cover me for 4-years to 148k miles for about $2,860.
I plan on keeping the car that long but a nice bonus is that if I decide to sell the warranty is also transferable. At that price and term it seems like a no-brainer on a turbo BMW.