They took a Beemer 530d around the track in a race against a (IIRC) 540 to compare horsepower vs “torques” 
In lieu of a proper explanation of what torque actually is, Clarkson did a fairly good job of getting across the feeling of a large turbo charged diesel engine.
That episode just aired over here. My favorite part was one of the other cars in the race put a sign on it’s trunk saying “Team Top Gear Please Don’t Hit Us.” 
Oh, and the sponsors on the doors of the car.
I less than three Top Gear!
Full of piss and vinegar - Vinegar - Piss =Taking the piss out of / Taking the piss = knocking something down to size in American.