No, you won't damage anything. The engine would far prefer to be on something more free flowing than a quiet restrictive system anyway.<div><br><div>The acoustics are fixed, the internals are a tuned work of art:</div><div><img src="http://www.ftypeforums.co.uk/images/converted_files/uploads/332/12441_17243.jpg" height="700" width="466" border="0" /><br></div><div><br></div><div><br></div><div>The overunn pops and crackles are 'induced' by the ECU. The fuelling calibrations are altered, in other words, it leans the mixture a tad. I have done with some of the carbs on my bikes, to produce an overrun 'pop'.</div><div><br></div><div>The exhaust flaps are opened and closed using a vacuum pump mounted on the left hand side behind the passenger seat.</div></div><div><br></div><div><br></div><div><b>Dammit, as I was tying this Scooby beat me to it! <img src="http://www.ftypeforums.co.uk/images/converted_files/smileys/smiley17.gif" border="0" alt="Tongue" title="Tongue" /></b></div>