My G56 system did not come with new bobbins but a set of these fit and you even get a spare one.

http://www.ebay.co.uk/itm/EXHAUST-BOBBIN...=item2a1c5e35d3

As mentioned, I also fitted 40mm diameter M8 penny washers on the inside (qty 12). You may like to get some stainless steel M8 nuts, washers and lock washers for the exhaust bobbins (qty 8 each). G56 supplied the 12 Allen head screws and washers for the brackets but not the M8 Nylocks, 12 of them required as well if you do not wish re-use the old ones. Nylocks are once only use locking device really.