The two GT racers with exactly the same output go up against each other in a track challenge.
Some vehicle comparisons can be tricky in that the cars that are chosen are not really meant to go up against each other.
They both dole out exactly 450 PS (331 kW / 444 bhp) - the M3 GTS from its 4.4 liter V8 unit and the 911 GT3 RS from a 3.8 liter flat-six engine.
Fifth Gear's Tiff Needell wins the battle for the best lap time with his GT3 RS beating Vicki Butler Henderson's M3 GTS by exactly one second.
But, no disrespect to Lady Henderson's driving, we can probably chalk much of that time difference down to Mr. Needell's masterly driving skills.