I’m looking to get a new exhaust for my car, preferably something a bit louder than the standard one. I can’t seem to find anything for a diesel engine however the Hornet 1.2 tsi one is the one I’ve looked at it. Would this work on the diesel car or should I go with something else and if so what ? 

I wouldn't bother, 3 pots sound dire when you start trying to make them sound better, it's just like advertising you've got no power.