well, i received the $3.60 air filter for the civic and have different results this time...this cheap filter looks to be manufactured better quality than what was in the car before. it's unknown what brand it is, but it's likely a more expensive brand bought from one of the local chain retailers.
I'm on a, oh, 13 year 80,000 miles replacement schedule so the cost/mile is pretty close to zero. However the el cheapo WalMart or parts store filters on sale (usually Frams) are just as good as anything, or maybe even better.
Old EPA 23/33/27
New EPA 21/30/24