It's strange. As far as I know, the turbo charged cars can't be influenced by the shape of intake and filter much. Sometimes, turbo charged cars put the filter on turbo charger directly. I did this on my previous car which has after market turbo chager and got a better dyno result. The amount of air is a critical fator for turbos. The shape of intake is not the point unless the intake shape is very ugly. The point for turbos is how much amount of air is gonna be sucked up by the filter. The stock filter can not suck up the air as much as AFE. I think every one would agree with this point.
I don't expect 27hp from AFE. I think nobody would believe that 27hp number, but loss of hp compared to stock filter? No way.....It's impossible. If it's right, time to sue the company!!!! Waste the money for nothing!!!