Help

Hi I am after some advice.

he exhaust note in the car goes loud like its blowing when its under 3000rpm. Its a little irrotating as I got a new exhaust (cat back) off ebay (car it came off had only done 36k) any ideas ? is it a common issue ?
the manifold was changed last yr

Any idea what it could be.
 
Check the centre exhaust mounting and have a drive with the diffuser off to confirm if it's the back box
 
Turn the car on, get someone on the pedal and feel under the car, mine did start blowing at the centre silencer. But obviously the common place for it to go is at the flexis.