Without question, the most talked about tidbit to come out of GM's new product presentation was word that internal testing of the upcoming Chevy Volt saw it generate a mind-boggling 230 mpg city driving equivalent under the current draft EPA federal fuel economy rules that are expected to apply to plug-in electric vehicles. While Chevy deserves kudos for backing that claim with an equally brilliant viral ad campaign touting what will no doubt be some truly spectacular city fuel economy numbers, it took little time for the EPA to respond that they're still a work in process. The mileage overlords immediately issued a statement applauding "GM's commitment to designing and building the car of the future -- an American-made car that will save families money, significantly reduce our dependence on foreign oil and create good-paying American jobs." However, the agency also pointed out that it "has not tested a Chevy Volt and therefore cannot confirm the fuel economy values claimed by GM." In response to the Volt's stunning mileage claim, Nissan issued its own release on Twitter claiming that the upcoming LEAF pure electric vehicle will generate the equivalent of 367 mpg in the city cycle using the same projected draft procedure. Whenever the EPA does finalize its electric/hybrid electric/plug-in hybrid electric vehicle testing procedures, expect the highway and combined mileage ratings for both the Volt and the LEAF to be substantially below whatever their city figures they earn. However, it's also virtually certain that each will be able to boast triple-digit overall marks.