This new BMW M3 Competition xDrive is full of surprises. Not only is it bonkers quick in a straight line, due to its added traction, but it’s also damn-near unbeatable on track when compared with similar cars. None of its in-segment rivals can beat it when it comes to timed laps around almost any track and it takes far more focused sports cars to beat it. To see how truly fast it is around a track, though, Auto Express decided to pit the new M3 xDrive against a purpose-built, ultra-lightweight, track-focused sports car — the Caterham 360R.

First, let’s check the specs. The BMW M3 Competition xDrive uses a 3.0 liter twin-turbocharged inline-six engine with 503 horsepower and 479 lb-ft of torque. Paired to that is an eight-speed automatic, which drives all four wheels, via BMW M’s rear-biased xDrive all-wheel drive system. It’s also quite heavy, tipping the scales at 1,855 kg (4,089 lbs), and has four doors, seating for five, leather seats, and a fancy infotainment system.

While the Caterham 360R is a far different vehicle. Instead of being a four-door sedan, it’s a two-seat, open-top, open-wheeled roadster, purpose-built for the track. It might only use a 2.0 liter naturally-aspirated engine with just 180 horsepower and 143 lb-ft but it only weighs 560 kg (1,235 lbs). It also uses a six-speed manual and rear-wheel drive, which might be slower but makes it more fun.

Sure, the M3 is far more powerful, packs far more torque, and has more grip. But the Caterham’s lighter weight gives it 321 horsepower per ton, while the BMW M3 only has 271 horsepower per ton. So the Caterham has a far better power-to-weight ratio. So which is quickest around a track?

You’ll have to watch the Auto Express video, in which Steve Sutcliffe gives both cars his very best around a tight, technical track. To be honest, the results really surprised me and I think they’ll surprise you too. Check it out.