At the heart of the system are three banks of non-volatile (fire-proof) lithium-ion phosphate batteries which store 30-35KWh of energy. One pack is located under the hood along with the 500hp motor and its controller (which also handles regenerative braking), the second pack is located under the trunk (in the spare tire area), and the third is located under the car along with the charging system (presumably replacing the gas tank). There are two range options -- 100 miles and 180 miles (rated at a constant speed of 65mph) -- the latter sacrificing some luggage space in the trunk.
Performance is impressive, at least on paper: 0-60mph in less than 6 seconds with a top speed of over 120mph. The kit provides a generous 300hp and 300ft/lb of torque, matching the specs of BMW's current 335i. It only takes 2.5 hours to fully charge the batteries from a 60A circuit and the 12KW charging system uses a standard J1772 socket compatible with both Level 1 (110V) and Level 2 (240V) charging stations. Donor cars can be either automatic or manual, the latter usually operating in second gear (and fourth gear on the highway).
Inside, the vehicle continues to look and feel just like a normal 3-Series. A custom computer interfaces with BMW's stock ECU via the OBD-II port and communicates via Bluetooth with any Android tablet or phone running the company's app (iOS is not supported yet). The app displays gauges for total power, current and voltage, fuel economy (typically 90-100 MPGe), charge level and battery temperature. Upcoming app functionality includes navigation integration and settings for performance / economy driving modes.
Pricing starts at $15,000 and Electric Motor Werks is now taking orders. Future plans include electric conversion kits for the 5-Series (likely the BMW E39) and newer models.