What are the benefits of fitting an aftermarket panel filter? Is there any real gain and what brand should I try?
any help would be great!

 

green cotton is well liked ....... and well recommended.

Gary

 

What does it do compared to a normal one?

 

Benefits are small, but there will be an increase in airflow which is no bad thing. Green, K&N and JR Racing come well recommended on here (I have JR) but there have been concerns over ITG filters damaging MAF sensors due to excessive oiliness, mainly on 98-00 cars with delicate hotwire MAF's. I can also recommend the free airbox mod which is the removal of the ram-air scoop and inner wing intake resonator along with the sealing off of the airbox from the engine bay. It allows a clean and plentiful supply of cold air to be induced from the o/s wing. As an added benefit it makes the induction, spool-up and dump valve audible. Details here

 

I used an ITG filter for a bit and the ******* thing halved my fuel consumption!

Use a cone filter now - wicked wastgate noise

Andy