I have a Mk 2 and want to remove the heavy rubber panel inside the side panel airbox side. I think it's just sound proofing. Is this correct? I presume it has no sealing effect on the airbox and is safe to remove?
Also, i read about removing the plastic baffling in the airbox so it can breath better (i'm running a K&N in there), is this a quick gain or does it affect jetting?
Thanks.

Yes you can remove the rubber sheet, I think like you, it acts a sound deadening of the induction roar.
Why not add some breathing holes in the top of the airbox?
Keep checking the plug for any sign of weak running though