We test a plug-in version of the largest, most luxurious Mercedes sedan, wonder if Nissan is charting a change in the direction of its battery sourcing, and get some of the numbers that matter for the Kia Soul EV. This is The Week In Reverse for Friday, September 19, here at Green Car Reports.

A plug-in hybrid version of a luxury icon, the Mercedes-Benz S-Class, goes on sale in the U.S. next spring. But this week at Green Car Reports, we already posted our first drive of this flagship plug-in, which will go 15 miles or more—and up to 70 mph—in all-electric mode. We also took a look at the smallest Mercedes, the CLA, and why it's such a sales hit.

And sales of natural-gas vehicles remain stubbornly low. Why are they, as a reporter put it, the 'neglected stepchild' of green cars—even when in California they'll get you a carpool-lane sticker? It all comes down to the where, and when, of how you can refuel.

Once again, several of the most popular stories from the past week pertained to the California automaker Tesla Motors. Tesla won a battle with dealerships in Massachusetts, assuring that its direct-sales model is legal in that state. And a regular dealership commentator, in the trade journal Ward's Auto, came close to calling the state-by-state battle against Tesla a lost cause. Meanwhile, a new report suggested that the cost of Tesla's upcoming Model 3 might top the $50,000 mark—because of the battery cost.

Cost itself appears to be the reason why Nissan is reportedly reassessing its plans for global battery sourcing. While not yet confirmed by the automaker, Reuters reported that batteries for Leaf electric cars built in Tennessee or England with locally assembled battery packs might soon be sourced with batteries assembled in Japan. And equally surprising, the report said that, for future vehicles, Nissan is considering batteries sourced from LG Chem rather than its own joint venture.

And those looking to go electric but keep their costs down have one more new option: the 2015 Kia Soul EV. This past week Kia priced this boxy, all-electric hatchback, which has an estimated EPA range of 93 miles, below the $35,000 mark. And if you're willing to forgo the federal tax credit, leases are starting at $249 a month. But there's a big hitch: If you want one this year, you'd better be in California.

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