Is your Focus an automatic or a manual? (I'm guessing automatic) My dad has an 08 Focus with a 5 speed, and that's a fun car to drive. I may consider getting one myself. I'm eager to see how a Focus will respond to WAI.
Power loss is dependant on engine load in my experience. While on the interstate in 80*F ambient, I'm seeing 140-150 IAT and feel no power loss because I'm already up and cruising 60 mph. While in the city, say a traffic jam, if I'm needing low end torque and IAT's reach 160+, I can feel a big difference... the power is just gone. Above 3,000 RPM the car falls even more on its face. It's pathetic.