The EPA's window sticker carries figures of 117 MPG-equivalent for the car on pure battery power, 39 mpg combined once running on its twin-cylinder gasoline generator, and an electric range of 72 miles. By way of comparison, those electric numbers are a little lower than the lighter, all-electric i3, which hits 124 MPGe and has an 81-mile electric range. They're higher than the leading range-extended car on the market though, Chevrolet's Volt--which returns 98 MPGe and 37 mpg combined on its four-cylinder engine.
What the i3 REx offers that its all-electric counterpart doesn't is reduced range anxiety, as combined range for the battery and engine is 150 miles. If previous plug-in cars can be used as a metric, few i3 drivers will regularly venture into gasoline-burning territory, but as a "get-me-home" option it could prove attractive to some. So will the fuel bills--the EPA sticker calculates an annual fuel cost of $650, based on 15,000 miles per year at $3.75 per gallon and $0.12 per kWh of electricity.
BMW has already announced the pricing and performance of its range-extended i3. The i3 REx starts at $46,125, or $3,850 more than the battery-electric version. That price includes a mandatory $925 delivery fee, but doesn't take into account any local or national incentives or tax rebates that may be available to buyers. Power comes from a 170-horsepower, 184 lb-ft electric motor driving--as with all BMWs--the rear wheels. The 0-60 mph performance is in the seven second range, and if range isn't a concern it'll hit 93 mph flat out.