Something of an engineering icon, Treser personally project managed the development of the Quattro, following his tenure as head of Audi's Advanced Special Vehicles division. Having moved on to head up Audi Sport in 1980, his contribution to its rally program then laid the foundations on which that car's legacy would be built.
Following his departure from Audi, he turned his attention to creating his own brand, founding Treser Automobiltechnic und Design. With the likes of AMG and Alpina in his sights, he was ready to show Germany's premier tuners how it was done, and the Audi Quattro was the perfect place to start.
Treser's fettling raised the power of the 2,144cc five-cylinder engine from 202 to 253hp thanks largely to a custom cylinder head, camshaft and exhaust system, as well as higher capacity fuel injection and a much, much bigger intercooler. Suspension was lowered with new springs, extended wheel arches housed those oh-so-80s wheels, and new bumpers front and rear were joined by a wraparound wing. The price for all of that came to a grand total of £25,600 in 1984, the equivalent of £57,500 in today's money - or bang in between an S5 and RS5...
Despite the many nips and tucks, the finished product was far from Frankenstein's Audi. As you'd expect from a man so intimately involved in the development of the original car, Treser knew what he wanted to improve and what could be left alone - hence the engine's unmolested bottom end and the standard brakes and dampers. In this way, we can think of the Treser as the money no object vision that one Audi's most influential engineers had for the Quattro.
The particular example we have here was converted from new in 1984, has covered only 36,000 miles since, and looks to have been impeccably maintained. Whether that, and the car's remarkable heritage, make it worth the £43,000 being asked though, well, we'll leave it up to you to decide.
Why you should: 80s icon tuned by a man who knows about them
Why you shouldn't: Does an Audi Quattro need messing with?
See the original advert here.