The engine is basicaly an airpump. The better you can make it pump by improving intake and exhaust will help it pump more at the higher rpms where the stock restrictions really show. At highway cruising speeds you won't see a lot of improvement. Gas milage may increase ever so slightly but not much. Gearing could help but at the cost of gas milage. A blower is the cheapest most effective way to increase low end HP because it force feeds the engine. The blower also won't effect highway gas milage, just around town milage cause you can't keep you foot out of it because it's so fun. This is the price you pay for big wheels and tires as it takes Horse Power to move that stuff down the road. Bummer huh!

I live in the mountains of Colorado and my biggist complaint with the VX is it's automatic transmition. The first auto I have ever owned in my 33 years of driving. When going uphill the transmition shifts constantly trying to maintain speed. Of course the power button helps and one of those intercepters that Tone sells would help too!. The intercepter may help you too!. Of course I want a blower and the intercepter but if I did that my wife would want the same on her's too!. She says no, but once she drove a blowered powered VX I think her mind would change. I know she loves the hill climing power of our 944 turbo.