The Chevy Spark's main electric traction motor will be 85 kW (114 horsepower) and be built close to Baltimore. That's less than the Volt's 111 kW (149 horsepower) motor, and of course it lacks the Volt's generator that can be combined for even greater power and efficiency at higher speeds. As such, the Spark is unlikely to match the Volt's top speed of 100 MPH. Perhaps 90 MPH is more realistic. Hey, at least acceleration is certain to be very strong, as with all of its peers.
The main unanswered question about the Chevy Spark's specs is the size (capacity) of the battery. The two main class benchmarks here are the Nissan LEAF and Ford Focus, at 24 kWh and 23 kWh, respectively. Given that the Spark will most likely be a lighter car, it could do with a smaller battery and still achieve the same range.
However, if GM is smart, they would ensure that the Spark achieves an EPA-certified range of at least 100 miles, as discussed above. That likely means that it must have a battery of at least the same size as the LEAF and Focus. Perhaps something closer to 30 kWh.
A light car such as the Spark should be able to get almost four miles per kWh, so a 30 kWh battery would yield 120 miles, which would be a sweet spot for this car, beating its main competitors in the market today. Let's hope Chevrolet achieves it.
Here is the mystery question for GM: Given the solid experience with the Volt, why isn't this Spark Electric hitting the market one year earlier than it will? It ought to be in the market right now -- not 10 to 16 months from now. The only legitimate excuse must be that it achieves a superior efficiency of meaningfully more miles per kWh than any other similarly sized competitor. If Chevrolet doesn't achieve that target, it is likely to be viewed a failure.