+1. Take the back box off and se if you can live with it. The turbo will kill a lot of the noise. Diesels, especially turbo diesels, dont need or want any back pressure from the exhaust and and run better the shorter and more free flowing the exhaust is. Any apparent turbo lag will also reduce as the turbo will spin up quicker. Petrol engines however are a whole different can or worms.Take the silencer off to find out, put it back on if you find it noisey, diesel is different to petrol regarding performance tuning mikescuba