The A1 was really just an evolution of the Gr.4 car, but homologated to fit the new Group B environment. It had it’s first rallye the 1983 Rally Monte Carlo, and the last at the Safari rally the same year. Price in 1983, ca 285 000 DEM.

Engine: inline 5, cast-iron block, alu-head, 10V, special steel-conrods.
Capacity: 2145cc by bore 79,51mm x 86,4mm stroke
Compression-ratio: 6.3:1
Power: 340hp / 6000 rpms
Torque: 414Nm / 3650 rpms

Early versions fitted with K27 turbos, while some used K26 at 0.8~1.9 BAR. Most significant was probably the use of the motorsport Pierburg-Bosch mechanical injection. Standard inlet- (38.2mm) and outletvalves (33.3mm) was changed for 41.1 and 35.2mm ones. Dry sump, Matter fueltank positioned in the trunk and a heattreated forged crankshaft.

Generally, the A1 introduced the lightweight materials to the rally typ 85s. Most noticeable is the wider fenders, the airinlet in front of the rear arch and Michelen decals. Matter had 3 versions of rollcages, in aluminium or steel.

Same dimensions as for the Group 4 car, but weight is now between 1130~1140kg.