The website only refers to the E71s with the smaller standard oval tailpipes fitted to the exhaust systems and not the type fitted to the 50i.

I would assume you can't fit them. They would look a bit odd as the rear bumper trim would have the wrong shaped hole too.

They do look good though. I am considering have the stock ends on my 40d replaced with the BMW retrofit kit that gives me the 50i ends. Why BMW did not fit them to the top Diesel trim I don't know.

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Me:
Current: 2011 E71 40D Vermilion Red/Beige Nappa

Wifey:
Current: 2012 R80 Countryman SDX Green/Cream