I have a 98 K2500 Silverado with 105,000 miles on it. I sometimes pull a 27 foot Fifth Wheel Trailer, as well as a 22 foot Pontoon boat. It has always been well cared for and garaged. My question is: What could I expect by puting a K&N air cleaner and twin exhaust from the Catalitic Converters back? Would it be worth the cost for any gain? Would I have to do anything to the Computer? I currently got 17 MPG on a 900 mile trip, empty, at 65 MPH. On the return trip, I got 16 MPG at 70 MPH (empty). Thanks.