I can't believe that a 3XZS system could use THAT much more fuel at highway speeds than my stock system unless they are REALLY inefficiant. After all they are both doing the same amount of work. Seems like if you can accelerate up to that speed w/o problems then it seems like it is a CONSTANT flow problem. I say take out the phancy BS filters and pumps, run straight to stock fuel pump. Un do the fuel line at the stock fuel line, put the hose down to the ground and see if you get a good flow for a pint or two (in a container of course.) Should get a flow like a pissn race horse. CRACK THE GAS CAP YOU MAY BE GETTING A VACCUUM BUILD UP IN THE TANK. I don't know about the new gas tanks and how they are vented but I would try that. And KISS it. (Keep It Simple S-----)