Okay guys, I've never actually seen the system in action. Does it really work well? What is different from the existing year vehicles? Also, how are they getting a substantial power difference between lets say, my 02 Z71 Tahoe's 285hp out of the little ol 5.3 and the new ones? I'm still a n00b, just wondering. Thanks fellas.

 

The wife just got a '07 Avalanche and the v8 to v4 mode is seamless. She isn't even broken in at it shows a average of 17mpg. Already better than the 01 Tahoe she was driving.
I think the power diff is tuning and variable valve timing. Not sure if the cam has changed but I bet it has. Someone can chime in on that one....

 

efans were put in also...starting in 05