I'm getting a really loud exhaust resonance between 3000-3500 rpm, I've improved the general noise significantly by wrapping the silencer in kevlar sheets and adding insulation around the fuel tank but the boom remains. Having just completed a 600 mile round trip at motorway speeds it has been a bit wearing to say the least. I normally use ear plugs to cut out the general noise but this resonance cuts right through them.

Is this a common problem on the K3? Do I need to be insulating anywhere in particular? I'm guessing the tubular manifold (std GTi) that sits close to the bulkhead is the main culprit?