Lancia Delta S4 Stradale
Why 3.4: A 1.8-liter four running both a supercharger and a turbocharger — the supercharger covers the low end and hands off to the turbo once it spools, killing the lag that made every other Group B car a lottery on throttle. The first twincharged production engine ever built. 200 Stradales homologated a rally car so fast it helped end the entire Group B era.
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Market value
Median asking price, good condition · €60k (1985) → €1.3M (2026), trending up · illustrative data
The long version
Lancia built the twincharged engine specifically to solve the problem that made Group B cars notorious — turbo lag on a loose surface is how drivers ended up sideways into a tree — by adding a Roots-type supercharger that carries the power delivery until the turbo catches up around 4,500 rpm. It worked: in period, the Delta S4 was one of the most controllable Group B cars to drive at ten-tenths, in the hands of a works driver. The road-going Stradale, built to satisfy the 200-unit homologation minimum, detuned that same engine from the rally car's 480-plus horsepower to a still-serious 247, in a 1,200kg mid-engine AWD shell with none of the electronic safety nets a modern car would carry. Group B was banned at the end of 1986, months after the S4's homologation run finished, following a string of fatal accidents across the category — which makes every surviving Stradale a relic of the exact era that got the whole class killed. That history, combined with genuine rarity, has pushed auction results past a million dollars; a car that traded for used-Golf money in the 1990s now changes hands for more than most houses. Nobody drives a seven-figure Group B homologation special to the shops. What's left gets trailered to concours lawns and the occasional closed-road demo run, not driven the way the works team drove it.