The research bellow was done by c32used of mbworld.org and by no way belongs to me... I give him credit here for his research...

Wanted to post the results of the 3 filters as I found this information very interesting...

"Ok Guys...

Here are the results on the track that tells differences if any with the more popular choices compared to stock air filters. Basically I see no major difference with the aftermarket filters but definitely see a difference with the stock filters. All runs were by the same guys with time inbetween for cooling while replacing filters. Conditions were near perfect for the SC cars. Its all preference guys between the two aftermarket filters. My preference is the Greens but the K&N seem better built. By the way if you haven't read my thread on this the K&N cleaner does a better job at cleaning the Green filters.

The 1st pic shows the best run with the K&N filters. (13.4360 @ 104.58)
The 2nd pic shows best time with Green filters. (13.4602 @ 103.93)
The 3rd shows best with stock filters. (13.9038 @ 101.60)

The 4th run well its my car besting a stock E55 who's non-owner driver made a huge burnout but almost caught me but I will take the momentary win
C32used 13.5780 @ 103.93 ChicagoX 14.9370 @ 104.89"