As many of you probably know there's an interesting story behind the MINI's exhaust tip and why it looks like it does:

Mini designer Frank Stephenson explains what a can of Budweiser and the new MINI have in common:
“We worked a number of 24-hour days trying to get the full-sized clay model completed for presentation to the board of directors,” says Stephenson. “So when we finished the job with just hours to spare, I thought it appropriate that the team have a beer or two to celebrate. That's when I spotted the problem.”

That problem was the complete absence of an exhaust tip on the otherwise complete clay. Thinking quickly, Stephenson stripped the paint from his beer can, punched a hole in the bottom, and fixed it in place on the model.

It wasn't long before he was called on the carpet by his boss at BMW. “It wasn't the shape (of the tip),” he says, “everybody liked it because it was unique yet oddly familiar. He was concerned that I had wasted a modeler's time milling the piece when his time could be better spent elsewhere. That was when I felt the need to confess.”

That confession got him stunned silence followed by nearly uncontrollable laughter.(BMWworld.com)

While the beer can tip applies to both models you can see the influence a bit more in the Cooper as it's single tip is larger.