So, having picked up a used Exige, I want to change all the fluids (Primarily the oils). My local Toyota dealership didn't have the 10004 filter, so I went aftermarket. I read the article by BOE about the 2009, so I wan't happy about only find Mexico filters. But when I opened the package, I discovered the design has changed.
This is the BOE article that I'm sure most are familiar with:
K&N HP 2009 Filter Comparison ? BOE Fabrication
I decided to take a look myself and found something interesting:
No secondary drain-back valve! The rest of the filter looks the same, but that extra valve is gone. Looks like K&N realized their mistake. The cool thing is that with the 8 inlet holes instead of the US filter's 6, extra filter media, and that "cheese grater" core instead of the small holes, the new Mexico filter may flow better than the original US filter.
If anyone is no longer buying the 2009 due to BOE's findings, it might be worth it to check one on the shelf these days. The revised design looks like a good choice now.