I have a 2002 Dodge Ram 1500 4.7 quad,installed K&N air filter, upgraded to mid grade gas and installed Flowmaster 50 series 943051 or URL
http://www.flowmastermufflers.com/cg...er/943051.html.
Before with K/N 15.4 MPG, with Flowmaster after 650 + miles 18.2 MPG. I'm sold and very happy with this install, at 70 mph continous i have seen averages of 21.2 MPG.total install for the pipe here in south cal with chrome tip single was $167.00 out the door.