[MetroMPG]

Just a note: keep in mind that a 4-7 mpg difference on an Insight won't equal a 4-7 mpg increase on a different car (should you try those tires on something else).

If the Insight's baseline is, say 60 mpg, that 4-7 mpg increase represents about a 7-12% change.

If your baseline is 20 mpg, that 7-12% change represents 1.3 to 2.3 mpg.

Just putting that out there.