Afternoon, I've got a Milltek cat-back system on my Bora 4mo but no matter how I adjust it the back box just doesn't seem to fit well and occasional I get a mild thud from it as I go over bumps or uneven roads. I think a back box of a different design would be the answer. Current Milltek back box looks like this. And I notice the blue flame system looks like this. Few snags with that though. 1) With the blue flame box being half the size I imagine it will be a fair bit louder than the Milltek? 2) The joining parts are different so perhaps I'm as well getting a custom back box made up?