The Audi RS7 Performance is a vicious $152,000 supercar wrapped in a luxury sedan

I never liked the Audi A7 much.

Since the German automaker first introduced it as the Sportback concept at the Detroit Auto Show in 2009, and later produced the hulking, four-door, four-passenger car in 2010, I saw the A7 as the red-headed stepchild of the Audi brand. You'll have to excuse the clichéd expression, but I was not a fan.

The A7 was long like an asphalt-bound freightliner, the steeply-raked roofline and the abrupt rear end gave the appearance of a squatting, hump-backed brute. Its dour rear fascia - the taillights and rear bumper collectively - had a sort of perma-grimace to them, like a bulldog.

It's an odd car in an Audi line that is internationally renowned for graceful European design. For me, the A7 was a car that never should have been made.

But another version of the A7 changed my mind. Audi Sport, the car maker's racing division in charge of pumping a select few Audi vehicles with extra everything, transforming them into muscular road torpedoes dripping with horsepower, performed such a treatment on the skeleton of an A7, producing the twin-turbo, eight-cylinder, 605-horsepower RS7 Performance.

Audi recently sent me one in Panther Black Crystal for a weeklong test-drive. I figured this might be the one to change my mind.

Oh, my.