I'm going to check with the dealer mechanics here and see if they can shed some light on the matter.
From jan this year, our diesel has been better quality, to be "more in line" with Europe's. Now we get peugeot and vw etc..hi-tech diesels, wonder why bmw can't treat us the same as Europe now as well. Maybe they could offer an upgrade to match euro specs, now our diesel quality is better??
Ps If the compression ratio differance is only in the head, that would be the easiest change for us.