As the ETCC struggled, the DTM blossomed with Mercedes taking the challenge to BMW and Ford with their Division 2 190 E 2.3-16.

BMW won a third of the 21 DTM races held in 1988 (but no titles) although a repeat number of victories in 1989 saw Schnitzer’s Johnny Cecotto crowned champion.

BMW’s 1989 success marked another high point for the E30 M3 despite the increasingly serious challenge from Mercedes who had campaigned the first Evolution of their ageing 190 E that season.

For 1990, Mercedes were known to have a much more radical second Evolution in the pipeline and Audi were set to join the DTM too so, keen to see off their domestic rivals, BMW created an overdue third Evolution of the E30 M3: the M3 Sport Evolution.

Announced in December 1989, the Sport Evolution was the most extensively modified E30 M3 yet as BMW Motorsport looked to exploit the Division 2 class regulations to their limit and nullify the challenge from Mercedes and Audi.

Engine / Gearbox

Uniquely, the Sport Evolution was the only E30 not to use a 2302cc version of the fabled inline four cylinder S14 engine. Instead, this final iteration featured a power unit taken out to 2467cc (a gain of 165cc).

Each cylinder bore was enlarged from 93.4mm to 95mm. Meanwhile, stroke was lengthened from 84mm to 97mm which necessitated the installation of a unique long throw crankshaft. Special nozzles were also installed that sprayed oil under the pistons to keep them cool.

Other new equipment included more aggressive camshafts, larger inlet and exhaust valves (the latter now sodium-cooled) and a big bore exhaust manifold.