The Alpina C1 was based on the E30 323i and was among their most popular early models, providing superior performance over the unmodified car.
The C1 2.3 made 125 kW / 170 hp and 225 Nm of torque. 0–100 km/h was achieved in 7.8s. Top speed was 213 km/h. The extra power is due to special Mahle pistons, and a special exhaust and igntion system. It also received dry-sump lubrication and a short-ratio five-speed gearbox. Only 35 C1 cars were built, making it one of the rarest Alpina cars. As BMW released the 325i, Alpina responded with the C2 2.5 and later the 2.7 models, providing between 190-210 horsepower. The brakes and suspension were also upgraded.
The C1 2.5 and early C2 / 2.6* models used the M20B23 (2,3L) engine, but bore and stroke were increased to achieve a capacity of 2552 cm3. Alpina reworked the head which was ported and polished, installed harder valve springs and a hotter cam. The intake manifold was also reworked, and Alpina used a larger throttle body. Max power was 136 kW / 185 bhp, with 246 Nm of torque. Alpina claimed 0–100 km/h acceleration in 7.1 seconds. Top speed was 220 km/h. Only 74 cars were built.