Last week's media days at the Paris Motor Show were the usual mix of cars and marketing.

They brought together stunning concept cars, more prosaic production models under pin spots, and speeches laying out how important every single model actually was to the future of the automotive world.

DON'T MISS: Volkswagen XL Sport With Ducati V-Twin Engine: Paris Motor Show Photos

One of the genuinely interesting concepts, though, was the Volkswagen XL Sport.

It offers a Lotus-like case study of why tiny and light vehicles designed for ultra-efficiency can make remarkably interesting sports cars when you fit a small but powerful engine.

Volkswagen XL1 (European model), New York City, Dec 2013

Volkswagen XL1 (European model), New York City, Dec 2013

Starting with the low-production Volkswagen XL1 two-seat carbon-fiber coupe, VW engineers ripped out the heavy lithium-ion battery pack, the two-cylinder turbodiesel engine, and the electric motor plus associated electronics.

ALSO SEE: Volkswagen XL1 138-MPG Diesel Plug-In Hybrid: Drive Report

In their place went a 197-horsepower V-twin engine from a Ducati 1199 Superleggera motorcycle. (The VW Group owns Ducati.)

The chassis and suspension were thoroughly re-engineered for the demands of performance driving and cornering.

Volkswagen XL Sport concept

Volkswagen XL Sport concept

Up front, the bodywork is roughly the same, but the rear of the formerly teardrop-shaped bodyshell got much, much wider to accommodate wide racing wheels and tires.

MORE: Four-Seat Volkswagen 'XL2' Diesel Plug-In Hybrid Coming?

Overall, the spaceship-like XL1 has now mutated into a low-slung, aggressive-looking performance coupe.

A supercar it's not, with a 0-to-60-mph time quoted at 5.7 seconds.

Volkswagen XL Sport concept, 2014 Paris Auto Show

Volkswagen XL Sport concept, 2014 Paris Auto Show

On the other hand, quoted top speed is 168 miles per hour--pretty impressive on less than 200 horsepower.

Those figures are due to the XL Sport's light weight--under 2,000 pounds--and its minimal frontal area and overall drag coefficient of just 0.258.

The XL1 economy vehicle had a long gestation through several generations of prototype before it entered limited production of 250 units at a price well over $100,000 (in Europe only).

AND FINALLY: Ultra-Efficient VW XL1: Now An Urban Legend, Debunked By Snopes

We suspect that if feedback from the crowd proves positive, we may see a similar, low-volume run on XL Sport cars for wealthy performance-minded buyers.

Which would make the XL into a range of vehicles--meaning there may well be life in the rumored four-seat XL2 as well.

Stay tuned.

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