We drove the 2017 Audi R8 on the banks of Daytona; the second Aston Martin Vulcan arrived in the U.S.; and we learned the difference between diesel and gasoline engines. It's The Week in Reverse, right here on Motor Authority.

The Audi R8 is a world-class supercar, and Daytona International Speedway's road-racing circuit offers big speed as well as left and right turns. Put the two together and you have something very special. We were lucky enough to do just that and we found that the car has more capability than we do.

The Aston Martin Vulcan isn't your everyday supercar. It isn't even legal for the street. Only 24 will be built and three are earmarked for the United States. This week the second of those cars arrived at Aston Martin Cleveland. If you have $3.4 million burning a hole in your pocket, it can be yours.

Lexus has a great reputation as a luxury brand that offers comfort and reliability. However, Lexus has had one of the worst engines on the market for a decade. That changes this year as a new turbocharged 2.0-liter 4-cylinder replaces the outdated 2.5-liter V-6. We drove the 2016 Lexus IS 200t with the new 2.0 and found that while we're glad the old engine is gone, the new one has room for improvement.

The difference between gasoline and diesel engines is pretty fascinating. While gasoline engines ignite the fuel/air mixture with a spark, diesels do it with compression. But it goes deeper than that. This week, our friend Jason Fenske at Engineering Explained examined the differences between the two types of engines in a very informative video.

Sporty roadsters aren't exactly in vogue right now, but we still like them. As Mercedes-Benz prepares a new SLC (the former SLK) to be released in a couple years, the German brand has also updated the current car for the 2017 model year. It may not be a viable Porsche Boxster competitor, but the SLC is certainly a sweetheart.


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