CS3s are on my 19" 309s too so I assume they are fitted to quite a few new X3s, and despite this, BMW can't source them, and yet they charge for "insurance". Hmmmm.
Not sure what the smallprint says but can't you push for both tyres being replaced on the claim, or accidentally drive over another nail?!
Let us know how you get on - good luck
F25 xDrive20d SE __ professional multimedia package | dynamic package | climate package | 309s | xline | xenons | electric seats | folding mirrors | business speakers