Here is some advice I posted on another forum. I thought I would update the topic here as well.
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DON'T BUY the 4cylinder Taco if you think you're going to get way better MPG... it's not worth it. I've had the 4cyl 3RZ for years (that you have to shift when the wind goes against you) and have watched my friends drive around effortlessly with their V6 power. And if you are putting larger tires on the 4cyl you surely have to regear or you will really be miserable. Only buy a 4cyl if you are getting a hell of a deal. Your foot will be into that gas pedal much more than if you were driving a 6cyl and that just throw more gas into the fire. You won't hardly save any money at all.