I brought an OEM air filter for the engine at the mini dealer (same part number). i came home to install it but the filter was just wider than the original. what i did was squeezed the pink rubber like substance in and screwed in the box. (took more time than ever!) however there was a millimeter gap between the cover and box.

im thinking about using this filter until 10,000 miles and buy an aftermarket.

 

There may have been some kind of error in either boxing or what the parts guy gave you. You were very clear on your car's build date? If the filter was not exactly the same size, I wouldn't have used it. Unfiltered air is getting in that 1mm gap in the box.