Hi flow cat without a tune

[El Andrew]

There are a lot of strong opinions on this one all over the internet. From my experience with my car (BA with100 cell cat and factory tune) the factory wastegate setup seems to be fine at controlling the boost. It comes on a bit quicker but catches the rising boost ok.

Since the new cat back system went in in comes on boost a lot quicker (I was quite surprised at the difference it made - I wasn't expecting any) and peak boost is slightly higher before the wastegate catches up and pulls it back a notch. But can still get right up it and doesn't go over the factory boost limit enough to trigger a fault.

The only down side is that it feels like it just starts to rocket and then the wastegate trims the boost back to what the factory tune is commanding. You just get a half a second taste of what the car could be with a tune.

I bought the car at 130k, so of course it is possible someone has made a modification in the past that I'm not aware of. So your experience could vary.