It was at a BMW dealer.

I've looked into my invoice, in the comments in the top, there is this description: "Replace the intermediate levers and upgrade crankcase". They told me that the upgrade was for cold-climate. So they improved the cc, they didn't installled an improved cc, sorry for the confusion.

From the part list, I think these are the one related to the cc fix:
11-12-7-563-474 (cover)
11-61-7-563-476 (pipe)
11-61-7-550-466 (heater)

I have other items that seems more related to the intermediate level change.

I would be glad to send a few pics, just help me locate the interesting spot (all I know of my engine is what's visible from the top, valves covers, spark plugs). I have no idea where the cc is...