http://www.ebay.co.uk/itm/VW-POLO-G40-58MM-SUPERCHARGER-SUPERCHARGED-CHARGER-PULLEY-AND-SHORTER-BELTS-86C-/140684400231?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item20c1719667
great if you have a steady supply of chargers and straight road!
my mate made something about that size and it was literally undriveable