I purchased my hemis for the gas mileage. I think 13 mpg average is great. I had many 454 chevy's, lol. See why I like the 5.7's gas mileage. My old 454's, maybe 7-8 in town, max 10 on average.

 

I found this on allpar.com

"Chrysler engineer Cole wrote: "The modern HEMI always shuts off the same four cylinders. In our duarability test cycle (150,000 customer equivelant miles driven at the 95 percentile, meaning that only 5 percent of our owners are more abusive than our testing), we have not found any adverse wear patterns." (Chrysler PR materials boasted of “over 6.5 million customer-equivalent miles through development and durability testing.”)"


http://www.allpar.com/mopar/new-mopar-hemi.html

 

I would assume wear would be even, and I bought my Hemi for the power not the mpg.