Originally Posted by SnAzBaZ
This is my pressure sticker. They don't mention 235/40/18's and no mention of M&S tyres. It's a 2012 Coupe DCT with Competition Pack.
BMW updated the winter tyres for the M3 Competition pack and are suppose to have 245/40 R18 winter tyres unlike the earlier 235/40 R18. But there's no harm in using the tyre pressure indicated for the 245/40 R18 on your 235/40 R18.
Edit: I've just checked my placard, which is also the comp pack version, and it's also 245/40 R18 for winter tyres. I believe it's 245 to help with ground clearance given that the comp pack is 10mm lower and using a 45 profile with 235 section would be too tall a tyre, while 235/40 would obviously be too low for the comp pack.