Power from the engine is passed through an AP Racing sintered clutch into a custom built Hewland HP2000 Sequential gearbox. A hyraulic ZF plate type differential is used to help traction which has the benefit of allowing driver adjustment during the race. Wheels are MIM cast magnesium alloys, measuring 18inch X 8.2inch wrapped in Michelin rubber, and they hide Brembo groved and ventilated cast iron brake disks. The Brembo brake callipers, 8 piston front and 4 piston rear, are based on those used in the Alfa Class 1 touring cars and feature four Performance Friction carbon metallic pads per wheel at the front and two Pagid pads at the rear.

The 155 suspension features MacPherson front struts and a trailing rear arm set-up, which must also be used in the race cars. Eibach springs and Bilstein non-adjustable mono-tube dampers are fitted, both of which have been specifically developed in conjunction with Alfa Corse. Abarth fabricate steel trailing arms to replace the standard cast-iron versions and both front and rear anti-roll bars are driver adjustable.

Inside the cabin is a Sparco racing seat and TRW Sablet harness. The 155 has a power steering system identical to that used by the Lancia Delta Group B rally car. The standard instrumentation is replaced by a Magneti Marelli LCD dash, which is also the front end for the data aquisition system. A fire-extingusher and fuel tank are also housed behind the driver, the latter being a 70 litre ATL fuel cell situated under floor where rear seats would normally be placed.