An earleir thread suggested that the Irmscher quads pipes did not have good flow properties or some thing like that.
Question is why should this be? I have them on my 2.2 direct and they sound great, but have never had the need to challenge the "flow" of these pipes. Has any one else done this or found that they do not perform?

I like the looks, but I am now getting a bit paranoid that I might be reducing my MPG some what or some thing else sinister.

At the moment I am getting 31 mpg around the doors (short journeys) and a long run on motorways at approx 75-85 MPH I can get 35mpg. Is this ok for what is a big motor with 2.2 engine?? Any advise would be great guys.