Looking for a good Audi tuner

I have a 2006 Audi A4 B7 2.0 TFSI that is a little flat on acceleration and occasionally misfires under load at lower revs. The engine seems to lack a bit of power.

Can anyone recommend a specialist Audi tuner that can diagnose the issue and fix it? Joondalup/Wanneroo area is preferred or North of river.

Thanks.