Does it actually work?
"If you’ve ever tried to autocross your Porsche® or even attempted to drive it to its limit on your favorite twisty road, you know one of the challenges is trying to hold yourself in place behind the steering wheel. By providing you with about 80% of the holding power of a full racing harness, the CG-Lock (the "CG" stands for "Center of Gravity") prevents you from sliding in your seat. The CG-Lock lets you keep your feet and hands light on the pedals and wheel resulting in better control, faster reactions, and less fatigue. Becoming "one with the vehicle" helps you feel the road and the car's "balance", enhancing your driving abilities. Just clip the tongue of your seat belt into the CG-LOCK to tighten and lock the lapbelt."
http://www.automotion.com/productpage.a ... +Belt+Lock