They reduce engine drag by slowing the engine down — without compromising performance of the vehicle or the performance of these critical components. (carparts.com)
This is true, but it is largely offset by significantly increased internal engine drag at high speeds. (mechanics.stackexchange.com)
Standard Equipment: 3.4 - liter horizontally opposed 6 - cylinder engine 6 - speed manual transmission Porsche stability management Engine drag torque control Automatic brake differential Brake pad wear indicators Tire pressure monitoring system Tilt / telescoping steering wheel Halogen headlights Cruise control Remote entry Two - piece manual top (automobilemag.com)