Mercedes' plans for a B-Class E-Cell Plus plug-in hybrid might headed for a change of direction. Take this all with a spoonful of NaCl, but looks like an all-electric powertrain made by none other than Tesla will be installed in the EV. As Autoblog Green notes, an anonymous spokesperson has reportedly claimed that the system switch-up is being made due to economics -- higher rebates and incentives are possible for zero-emission vehicles in the EV's US target market. No technical details were given on the new powertrain, but the original idea was to have a Volt-like 138-horsepower electric powerplant for the B-Class compact, with a 67-horsepower gas engine backing it up. At the very least, a collaboration between the two companies would make sense, since the Stuttgart automaker is effectively a five percent stakeholder in Tesla. So if you've been holding out for an EV with the Merc touch, check the source for the details.