Through the intake that is! A couple of weeks ago I replaced the stock air filter with the AFE Pro Dry S filter, which probably has helped although hard to say how much because... I found I had one of those double-sized styrofoam packing peanuts stuck in my intake. It had been trapped by the "snow screen", where I also found the expected collection of pine needles and other debris but was definitely not expecting this! I have no idea how it got there - the intake slot in the front grill hardly seems big enough for this to have been sucked in while driving. In any case, it's big enough that it would have blocked about one third of the screen.

The good news is that the sluggishness I was experiencing is totally gone now and the car has it's zippity back.

Moral of the story - check your snow screen! (Rather than take it out, I've decided to leave it in place and check it periodically). Also, if you are looking for an aftermarket low restriction filter but are turned off by all the stories about MAF problems with oiled filters, check out the Pro Dry S at ecstuning - no oiling, and cleans up with simple soap and water.