I did my research and found the cheapest Volant cai and scoop. Bought both, unfortunatly I was not paying attention to the scoop p/n and got one for a 1500 series. I have a 2500 burb. Did an oil change a week before cai and went with mobil 1 economy 0-w30. Fresh oil made a diff. and cai seemed to help also. Does anyone have a favorite cai or anyone with a volant cai?