My 2008 4 seater was 55 litres, and my current 2008 2 seater is the same. My understanding, could be totally wrong, is that the tank capacity was reduced when the advanced EVAP canister was mounted alongside the fuel tank at the rear. I would be cautious of topping the car off though, many instances of reports of rough running as any overflow goes straight into this EVAP carbon canister and instead of the system being purged of fumes it gulps in fuel, tries to adapt and then the check engine light comes on and you have a multiple misfire code stored in the OBD. Not the end of the world it will sort itself out but repeat instances are not healthy for your Catalyser.
