well the CAI doesn't really add any HP it just helps the engine breath better. When I installed mine I was thinking WOW, there would be a real noticable difference, but I really couldn't notice anything accept the cool sound it makes @ WOT. I laymans terms, It help when used w/ other mods but don't think the car will run 13's w/ just the CAI.
Not really. Headers let the engine breath out better. CAI
takes colder air from the front of the Hood
, rather than taking warmer air near the engine. The colder the air, the better it burns or something like that. And it does improve your horsepower. Not your flywheel horsepower, but the horsepower to your wheels.
For example: My GTS has 180 flywheel horsepower, but not all of that goes to the wheels.
Someone correct me if I'm wrong.