not sure, forgot to ask, i just said to david that id ring back in about 2-3 wks for an update, he said they have the unfinished version on their demo car an theyre really pleased with it (not like hes gonna say they arent) but credit to them, they originally said it would be out mid feb but they wanna sort out the boomy-ness issue by altering the middle silencer before it goes into production, he said it sounds well throaty on throttle, like the std zorst you wont see a thing as its tucked up behind the bumper, am 95% sure this is the one for me !!!