I’ve got a straight pipe in place of my mid box on my TD5, it is louder, and you can hear a strange whistle when the thing is on tick over (from outside only), but as for more power/less lag, cant say I’ve noticed. It is strangely reminiscent of a chieftain tank when pulling away. One thing that did come to light was that it was over-boosting after fitted with a Jeremy Fearn intercooler and chip, which he did say was not something that happens with a stock exhaust system, so must be doing something.