Banks Intake and exhaust system

I installed a Banks system on a motor home with a 460 in it. I did some very careful testing pre and post Banks. Before the Banks I could never break 10 mpg, and this was on a 22 foot mh. With the Banks I got an extra .5 mpg. The real reason for the install was to cure the breaking exhaust bolt problem. The headers are just beautiful, but more noise from both the doghouse and exhaust.The part that's not worth it is the Ram air intake. Again I tested, and found no difference with the stock air intake versus the Ram air. I put the paper filter back in and just as good. The real benefit is in the headers.