Shows two options for an upgrade to a Yama 1/5th Scale Petrol Buggy Exhaust - Can be purchased at following Ebay Link.
http://www.ebay.co.uk/itm/Exhaust-Upgrade-Prototype-for-Yama-Petrol-Buggy-Opt-3-Side-Type-Big-Bore-/131948459067?hash=item1eb8bdb43b:g:d5oAAOSwPCVX5VWY
