Just replaced the stock air filter with aFe ProDryS drop-in filter, will report back when I find some time to drive the car. I plan to check it frequently in order to make sure that it makes proper filtering.
By the way, anyone who never did this himself before, it is the easiest job ever, totally straightforward, all you may possibly need is a small screwdriver to pop out the silver clips holding the air box in just seconds and maybe wet wipes or a good vacuum cleaner to properly clean the box before you drop the new filter. I really advise everyone, especially people who live in bad air quality areas to check their air box and filter minimum once a year regardless of mileage since there was a surprising amount of tiny stones, pollen, debris accumulated in there and also a few got stuck inside the filter, the kind of stuff you don't want get sucked in your engine. If you live near sand deserts, like certain parts of Middle East, I would totally avoid replacing the stock paper filter and instead change or clean the stock unit as frequently as possible.
Next, I will drive and see if there is any change in sound or response or just a big fat NADA
"The mark of a great car is one whose overall competence exceeds what you should expect from its individual components and the 1M does just that", Chris Harris.
2011 BMW 1M: TECH: Evolve Race+N55mids, Evolve IC, Michelin PSS, ER cp, aFe filter, CDVx, Vorshlag camber plates, P3Cars, OCC EXTERIOR: trunk spoiler, blacklines, black grills, IND goodies INTERIOR: Alcantara steering wheel, steel pedals, custom mats, MPower e-brake.