I dunno, probably only 5-15hp, which at 390hp won't change anything performance-wise. But I think the exhaust might be the most important part of the sound system ;-). You can hear samples on the 3200 coupe at Manu's site, www.tubistyle.co.uk (or www.scuderiasystems.co.uk I'm not certain). Just saying I thought the ones they had at the event sounded BAD. The good kind of bad. Either way, happy motoring!