Received my exhaust and couldn't wait, so had it fitted by Birds. Initial thoughts so far is that it is fantastic!
Fitment is absolutely perfect (I have a bit of a perfection OCD) so it definitely ticks that box. I would have liked the tailpipes to be about 2cm more tucked in, but nevertheless it still looks very OEM and I am extremely pleased. The BMW Performance diffuser does stick out more than the standard M-Sport one, if you want to overcome this; but like I said, its really if your picky. I think i'm going to leave it as it is!
Despite being named the 'Performance' exhaust, I didn't expect it to make any noticeable change 'performance-wise'. However, I was wrong and i am going to echo what Carlsson has already said - the car is definitely more willing to go and IMO it feels more like the F30 320D (which if you have driven will know it feels pretty rapid, in comparison to the E90/E92). Pick up on second and third gear has definitely improved and it seems to have more lower end grunt, which I think the 320D lacked a bit in standard form.
In terms of noise, the engine note doesn't change. It still sounds pretty much the same when idling and at RPM below 3,000rpm. Anything above and you can hear the exhaust note. Its very subtle and you can't pick it up from the cabin much, unless your window is down. Some may be disappointed by this, but IMO a Diesel is not going to sound great with a lovely howling exhaust, and the diesel clatter behind it at low RPM. Its just as well that you can only hear it when you rev it more, as the car sounds less diesel like then!
Overall - am I happy and do I think the mod was worth it overall - definitely 100%!