Just a bit of an update, Sarah is on the case with Milltek They've asked for the batch number etc and we've sent that to them, unfortunately the noise has become a bit more erratic and it's difficult to pin down but this seems to tie in with problems other guys had a while ago with M3's. Apparently the box on the mid section has been known to fail but it seems when Milltek confirm the problem they replace the box straight away, hopefully this will be the case. I've got the local tyre and exhaust place on stand by and we're going to see if we can reproduce the noise and then get it straight up on the ramp, fingers crossed, we really could do with a fingers crossed smilie