Ok i did my airbox today. Didnt do too much but basicly just removed the flap inside so only cool air enters rather than the hot from the exhaust manifold. I found my flap was not closing fully so never got true cold air ever. Open up your air box and remove the top part with filter. Trace the vacum pipe from the inlet manifold and block it off. this is the one that ultimatly operates the flap. On the flap housing you will see where the flap pivots. Drill into the housing here to start detaching the flap. This should destroy the top part of the pivot of the flap. With any tool possible just destroy the flap and pull it out cleaning and debris. Remove the hot air supply pipe and blank it off at the airbox with something strong like gaffer tape. Make sure it will take the vacum of the engine pulling. Now your car will get a nice free flow of cool air, will not sound loud and annoying and will give you something to do :)

What does this do in relation to the car's performance (if anything)?

thanks for that i may just have to have a look at this i was wondering how i could get around removing it without buggering up the ecu

yes it will increase the fuel comsuption but not enough to notice really any power inproving mod is going to increase mpg

Fair enough. Don't suppose you've got any piccy's of what you did Dog?

Not yet :) its sort of easy enough if you have a look at your box in day light. Just rip that stupid valve flap thing out and your away :)