I have been running for most of last year and so far this year something thats known as a fogged air box, this is where the air box internals are removed, and the air intake pipe is repositioned so it gets cool air from the front of the car, I have been looking around for other options to try, and noticed something called a ‘gruppe m’ which is supposed to give you 5-7bhp gain in power, but these are a lot of money, so I dropped on a second hand replica the other day, and will try to get this to fit, its not exactly the correct model for my car, but I am sure it can be made to work.