The 156 engine is based on a Fiat modular designThe alloy twin-spark cylinder head was developed by Alfa Romeo Each cylinder has its own ignition coil for improved engine performance and reliability Variable valve timing improved performance at both high and low engine speeds Concealed rear door handles suggest two-door coupe styling Bosch anti-lock four-wheel disc braking system uses electronic brake force distribution to maximise braking effort To protect against rust, 65 per cent of the 156's steel is galvanised Front seats are constructed partly of magnesium and use anti-submarining design Front seats are height adjustable Climate-control equipped 156 models have a two-stage air filtering system to remove pollutants and pollens Heated external mirrors assist vision on cold mornings Leather seat trim is available as an option