On the subject of gas mileage...
The '07 Sienna that I bought my wife had an EPA window sticker showing 19 city / 26 highway mpg. Toyota made no drive train changes from 2007 to 2008 but the testing methodology changed. The result was a window sticker on the 2008 models that show 17 city / 23 highway mpg.
Ours runs 18 to 19 mpg in town but we ALWAYS get 27 mpg or better on the highway. The highway miles are typically at 75-80 mph with the cruise and a/c on. We've topped 30 mpg on the highway on an extended trip at slightly slower speeds.
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"There is not a man of us who does not at times need a helping hand to be stretched out to him, and then shame upon him who will not stretch out the helping hand to his brother." -Theodore Roosevelt