Tinkering with the Roadster yesterday and a had the chance to measure the later version of the alloy tank the factory fit
I cubed it up (deducting the chamfer to the rear edge) and got 90 lts, that's over 19 gallons ! way over what I expected and what the MMC quote
Even though you'll never fill it to brim full with the airlocks, it gives a useful boost to range - although the 90 odd kg of weight is a lot to lug around
