I was just browsing a website and I came across this. It says

"Reshape your factory throttle body to boost airflow velocity and power!
These all-new VR Velocity Stacks from VaraRam are the solution for poorly designed GM throttle bodies. Installation takes just minutes. They will help you increase power output throughout the entire rpm range, improve throttle response, and increase your gas mileage!"

<img>http://static.summitracing.com/global/images/prod/large/vrm-vr-3.jpg</img>

Im calling , but was wondering if anyone had any input on these

 

All in all if it does do anything I'm not sure. I do believe a ported factory TB is better.