Nobody has gained power and everyone has lost power with the AFE. Some just feel it more than others. When this came out on the 5 boards people were raving about it how they felt their cars were quicker and better. It usually was from the aggressive sound that played tricks. But when dyno after dyno started rollin in showing 10-20 hp loss with these things after anything more than 10 minutes of driving, it became real clear what was going on. Major heat soak with an open filter to the engine bay-terrible design.
This is evidenced by the inake in the m3 is now a totally sealed closed design and AFE even says they did this because open intakes have heat soak!
You can get away with this for a turbo since the air being sucked in is already hot (exhaust) so this will not matter but for an NA engine more heat is absolutely parasitic.