Originally Posted by
MetroMPG
Here's a thought:
Mitsu's plastic wheelcovers are pretty darn flat/smooth (currently one of the smoothest OEM ones I know of). Replacing those with perfectly smooth covers probably isn't going to make a significant MPG difference -- too small to easily measure. So if your goal is saving money, you'll have a veeeeeeery long payback time if you spend much money at all on replacements.
On the other hand, the cars with alloy wheels are going to see the bigger improvement, so could afford to spend a little more. Bang for your buck, in both cases DIY is the way to go of course.
Aesthetics are usually the issue with DIY.