Hmm. $3800 for no increase in fuel economy. But surely it should be faster than the Eco with 148 hp and 258 ft/lbs. Oh but no manual option...
My guess is that the real world MPG numbers will favor the diesel over the gas engine though.
Mine: 2004 Subaru WRX Wagon: 116k, WRB
Gone: 2002 SVT, #1654
Hers: 2012 Focus Ti Sedan: 67k, SGM, Manual