I have the non resonated milltek from the turbo back with a sport cat, and all i can say is WOW!!!, what a difference it made in throttle response, noise and how quickly the turbo spools up. It is a very good system, and well worth the money. Many people who have heard mine will say, that it sounds awsome for a riesel once under load and up and running, but at idle, it still sounds like a diesel, but a bit deeper note.
Before i got the car i thought what is the point in getting an exhaust for a diesel? as it will sound ****, but how wrong was i? very. It sounds fantastic, better than a petrol i would say, but then again i do have a hybrid turbo to make it go and sound well.
I would say go for it mate, you wont be dissapointed in your purchase.