I have my bugeye de-catted back to the turbo down pipe after that if you replace the down pipe ie taking out the cat i'm pretty sure you need a remap,mines is pretty loud now that i got the mid section done but a full de-cat is pretty loud my neighbour had Paul Clarks old wrx and it was fully de-catted and was LOUD ,as for the local plod around here they aint really interested.
Stevie