Full review: www.autoexpress.co.uk We pitch Fiat’s new two-cylinder TwinAir against the pinnacle of the 500 range. The Abarth is faster in a straight line, but is it more fun to drive? Size matters. And for Fiat, it’s a case of the smaller the better with its new TwinAir 900cc two-cylinder engine. On the outside, there’s little to distinguish the two-cylinder Fiat from any other 500, but as soon as you turn the ignition key, it’s clear that there’s a very different powerplant under the bonnet.