At the 1970 Geneva Motor Show, BMW unveiled the 2200ti Garmisch concept car, a 2-door saloon which was developed in conjunction with Bertone.

[10] Computers were used in BMW development for the first time to calculate front and rear crumple zones; the roof was designed with a rollover protection structure.

[15] Instead, BMW carried over the 2-litre four-cylinder M10 engines from the New Class saloons, but modified the cylinder heads in order to improve combustion.

After the August 1976 facelift all models featured the same bonnet, with a narrow raised central section reaching all the way forward and wrapping around the "kidneys".

To meet Sweden's unique and stringent emissions standards, a fuel injected version of the 528 was developed and entered production in June 1977.

The 518 had its fuel supplied by a Solex 32/32 DIDTA carburetor,[21][22] while the initial 520 model (powered by the M10 inline-four engine) used twin Stromberg 175CDET carburettors.

The front wheels have MacPherson struts with coil springs, hydraulic shock absorbers, and transverse control arms.

It was rumored that this special version was produced for the Iranian government, as a car for top officials under the shah's rule.

For the Swedish market the complete BMW 5 range was not offered, due to local emissions regulations.

[35] Other modifications were a shorter differential ratio of (3.45:1 for the 530 and 3.25:1 for the 530i),[33] a 25% LSD, vented disc brakes, Bilstein shock absorbers, Scheel or Recaro sports seats, a sports steering wheel, alloy wheels on lower profile tyres, and optional front and rear spoilers.

[46] Significant weight reduction measures were undertaken, included body panels made from aluminium or thinner steel.

The hood was redesigned to a give a 'power bulge' which accentuated the BMW kidney grille, and the dashboard ventilation was repositioned to improve air distribution.

For the 525 and 528 models, the dual Zenith carburettors were replaced with a single Solex 4A1 DVG four-barrel,[54][55] which increased power to 125 kW (170 PS; 168 hp) in the 528.

[58] The North American E12 models had larger bumpers (designed to withstand a 5 mph (8.0 km/h) collision without body damage), which increased the overall length by 206 mm (8.1 in).

[60][61] Power was reduced by 5 kW (7 bhp), and the presence of the catalytic converter meant that unleaded gasoline (petrol) was required.

[62] In spite of widespread sanctions, locally built E12s also saw some export, the 520 being sent to Argentina and the 518 De Luxe to Belgium, Iran, and Italy.

[62] To keep costs down, BMW chose to continue building the E12 in South Africa after the E28 had been introduced elsewhere, with the body now pressed and manufactured locally.

[63] While being commended for its acceleration and build-quality, Modern Motor criticised the 1978 528i for unpredictable handling and excessive body roll.

[64][65] Steering corrections during cornering meant the car's body "lurches back annoyingly and messily", in part due to the soft springing and hard damping combination.

In comparison to the Jaguar XJ6 and Peugeot 604, the car was viewed as narrow and cramped in the rear and prone to wind noise.

[69] Complete knock-down assembly of German-produced kits took place in Rosslyn, South Africa;[70] Jakarta, Indonesia (by Gaya Motor);[71] and Thailand.