Sounds like you're getting pretty low gas mileage there. I get 34-35 MPG and don't start looking to fill up until 160 miles or so and usually takes about 4.5 gallons at that point. I've been over 180 miles before finding a station and, although I was starting to worry, I could have went another 20 miles or so..

I run a PC-III with TORs/ cat-by pass.
Sure do like the looks of the Jardines, as well as Travelguy's Predator exhaust system though.