I have had the misfortune to lose 3 TPMS sensors in the last 3 years on my 2012 GSA, which is a nuisance. I don't like riding along under the accusing stare of the yellow triangle. Having struggled to get a price from my local BMW shop for replacements over the last couple of days (!) I have looked on line and found dozens listed! No doubt all are from China, but that will be where BMW get theirs anyway? Anybody got any advice on where to buy TPMS sensors other than BMW dealer?