What do you think? Will the xle get the same mpg as le?
Some things to consider:
1. The EPA rates the LE at 41 mpg combined, and the XLE at 40 mpg combined. The EPA do not report down to the .1 of a mpg, and round off. The actual test results could have been 40.5 for the LE and 40.4 for the XLE. In other words the difference could be simple round off and is insignificant compared to the measurement error.
2. The only obvious difference in the models is the wheel and tire size. There is a small weight difference but that is probably insignificant. What you don't know is the specific tire used in the EPA test. Toyota would know, but I don't know where you could find it. The rolling resistance of the specific tire could easily account for the difference in fuel economy. It may or may not be more significant than the tire size. Consumer Reports data is unclear as to which tire may have lower rolling resistance.
3. The LE uses steel wheels while the XLE uses larger cast aluminum. Could the cast aluminum be heavier? That would be my guess. However you would have to weigh them to know. Significant?
4. The EPA tracks self reported mpg. Currently the average for the 2012 models is 40.2 for the LE, and 38.5 for the XLE. If you rounded them off like EPA does for the test data, that would be 40 for the LE and 39 for the XLE. It would seem that the very slight advantage of the LE is validated. Could it also be the those who buy the LE are more cost conscious and drive differently than those who buy the XLE? Or, is it the smaller wheels and higher profile tires on the LE?
5. In Canada I believe the LE comes with Michelin Energy while the XLE comes with Michelin Primacy. The revolutions per mile of the Energy is 786 while the Primacy is 791. This is in favour of the Primacy. It is reporting more mileage for the same distance traveled. This can be ruled out as the reason
The bottom line is that I think you would be chasing shadows trying to replicate the EPA test results, especially if you use cast aluminum tires instead of steel, and if you don't use exactly the same tires as they used for the EPA test. It is also very costly to change wheels and tires. You are unlikely to ever make your money back on improved fuel economy if you even get any. Best bet would be to keep the wheels and when the tires wear out do some research and buy the most fuel efficient version currently available. Tires are improving all the time.