[Ashley_rj]

Hi Guys,

I have a Harrop s/c e90 M3.
I have the full stock exhaust system at the moment but would like to switch to a high flow alternative. I am also a bit of an eco warrior (hypocritical I know) so don't want to go the decat route as this is my daily driver.
I would like more power (probably unnecessary as there are 490rwbhp).
There is very little info I can find about replacing the primary cats other than test pipes.

I have found that Cobra make a high flow cat'd front exhaust/up pipe/1st section or what ever it is called. As does supersprint, but I cannot find out any information as to whether this will give me some extra hp, be worth while, terribly affect my emissions.

A further option that I don't see why couldn't be done would be to cut out the primary cats and to weld in some GreenCat's or Magniflow's. If done well I dont see why that would not be a viable option???

Harrop does have a tune for a decatted exhaust, unfortunately the current staff there don't seem to be very clued up, so I have lost a bit of faith in their advice.

I would consider doing the rest of my exhaust also and will probably go for M3 world's x pipe and valved rear section.

Any info or opinions would be appreciated.
Cheers, Ash