The GForce ad was next to a Google email and so I had a look. Utter crap! I am a mechanic and they are not selling anything useful. When I filled in the select make and model it never asked for the engine type or tranmission type and model or the driving conditions or any other very necessary details. They say they will ask for the engine after you fill in all of the details but this is just a con to get your information and sell it.
When they do ask for the engine information it is free form and they trust you to define the engine type. Most people don't know what they have under the hood. Even enthusiasts and professionals can't be completely correct without research.
Read the reviews here:
http://www.performancechips.com/performance-chip-reviews.html The test car lost power and used more gas.
and
http://www.clubtouareg.com/forums/f64/gforce-performance-chip-whats-your-opinion-41916.html A pro talking about how GForce is lying.
Do not buy anything from these criminals! Tell everyone they are crooks!