Best Motoring puts the Porsche 911 Turbo to the test by switching on/off the PSM — allows you to get more power from the engine when enabled — while driving around a test track. Video after the break.

Best Motoring puts the Porsche 911 Turbo to the test by switching on/off the PSM — allows you to get more power from the engine when enabled — while driving around a test track. Video after the break.