What can you tell me about fuel performance chips which claim to interface with the ECU (Engine Control Unit). This is the main unit that the Performance Chip interfaces with to create more power, fuel mileage, etc.
I see that you have one question and the other three points are basic facts. To answer your first question - the simple answer is no, those performance chip you see in the magazines are falsely advertised. I think you have the GM engine in your 2008 VUE. The software engineers in GM that create the OE fuel map and A/F ratio already did their research and have optimized for maximum power along with MPG. Any modification to the fuel map setting will not be recommended.