This is what the man is talking about with his Group A8 car.

See under Air Box.

http://www.powerengineering.co.uk/mitsu/index.htm

 

I've got the same kind of box..but make your own it's cheaper and not that hard...just think back to metal shop class... the next thing I'm gonna do is cover the box with thermal sheets

 

Yeah. I just modified the original air box and dropped in a RalliArt filter. It works for me.

 

Would one of these "air-boxes" be better than an open or CAI design?

 

Actually, the boxes work in conjunction with CAI or other intake....take look at my ride...there are 2 pic of the engine bay. 1 with lid on the box and 1 without... The key is to reduce the temp of the air being induced to the engine, (to the turbo for turbo engine and throttle body for NA engine) What my pics don't show is I actually got air coming from the outside (front bumper) to the box from the right) My intake vent on my hood is not being used at this time.(But I have plans) The next step for my box is to cover it with Thermal sheets..alumnium as is works pretty well but all metals retain heat to some degree. The sheet actually reflect the heat back..hence even cooler ambient air for your intake. I was also looking into water injection but I haven't read up enough on the subject enough to make up my mind either way. Also consider the average climate of your area...My area barely gets to low 50's in the winter but in summer months mid to high 90 with very high humidity 89% and up
PS I have seen guys actually make their boxes out of wood and cover it up with Thermal sheets! It actually looked prety decent
PEACE