I've been using CG lock for a few events and 3 months on the street, this lock is amazing! It simply keeps my butt firmly in place, let me get the feedback more directly from my rear tires. Knowing when the rear end starts to slide is a big advantage.

It helps me to reach my steering wheel, brake and gas pedals more consistently, where I used to be all over the place even with a racing seat. I don't need to use my left knee to stable my body anymore and I can do Left Foot Braking!
Last but not least, CG lock is way cheaper than a full racing harness setup(FIA approved harness & harness bar AREN'T CHEAP. With the harness bar, the backseats are not safe for passengers), and yet still have the rear seats available whenever I have passengers.
This is my best "mod" I have done to myself and my car, for around $50 tax included(from PDM Racing, VCMC members discount price! Thx Don.) Now I can focus on my driving, not how to keep myself in the driver seat.