Ford Repair: My Fords, ford ranger 4x4, cold air intake

Question
I have an '03 Ford Ranger 4x4 with a 4.0 V6.  Although I rarely use my 4-wheel drive, I travel constantly in this vehicle.  I am putting a massive amount of miles on my truck.  I am wondering if there is a way I can increase performance while improving gas mileage at the same time?  I am lucky to get 300 miles on a full tank of gas while traveling the interstates.  What else should I do to add to longevity of this vehicle, due to the high amount of miles I drive each year?
Also, my wife has an '04 Ford Mustang with the V6.  Although she does not travel as much as I do, she also puts a lot of miles on her car each day.  Is there a way I can increase performance while improving gas mileage at the same time on her car?  She is lucky to get 260 miles on a full tank of gas in town.
Thanks for the advice.
Richard  

Answer
Richard-

  Unfortunately there isn't much to be done about fuel economy, but you can bump it up a tiny bit.  The most important thing is to make sure the engine is in a good state of tune.  Checking the timing, good spark plugs, and good plug wires are all factors in how efficient the engine is.  Really about the only other thing I can recommend would be an aftermarket cold air intake with a conical air filter.  One for the Mustang will be incredibly easy to find as many manufacturers market them.  The Ranger, however, might take a bit more looking, but I'm willing to bet they're out there.  Hope this helps.

Steve