It takes all sorts of people to make the world go around, and the same can be said about electric vehicles.

Some customers never want to touch a drop of gasoline again, and opt for a pure battery electric vehicle. Others like the convenience that a range-extended or plug-in hybrid electric vehicle gives them.

BMW offers you both with the 2014 i3, but if you're torn between the two options, which should you buy?

Long-time BMW electric program participant Tom Moloughney has taken a look at this question on BMW Blog, and his comments on each vehicle should help you decide which i3 model is the better one for you.

Much of that decision will hinge on whether the i3's 81-mile EPA-rated range will be enough to meet your requirements.

From a 22 kWh lithium-ion battery, 81 miles is enough to make the i3 the most efficient battery electric vehicle on the market, with a 124 MPG-equivalent combined rating (138 MPGe city, 111 MPGe highway).

But it may also be too restrictive for some buyers, which is where the range-extended model comes in.

Moloughney says prospective i3 purchasers can fit into four categories. The first are those interested in the car, but for whom 81 miles is too low and the REx model is out of the question.

The second can live with the 81-mile battery-electric vehicle (BEV) and choose it, knowing its limitations. The third--a group Moloughney is part of--would prefer the BEV, but have chosen the range-extended model for peace of mind.

The fourth group like the idea of the range-extender from the start, and buy that model.

MORE: Do The BMW i3 And i8 Electric Cars Pose A Threat To Tesla?

In effect, it's the same sort of decision other electric vehicle buyers might have gone through up to now, when selecting between two of the highest-selling models on the market, the Nissan Leaf and Chevrolet Volt.

And just like those two vehicles, it's the battery-only model that will cost you less to buy initially. Opting for the range-extended i3 will add $3,850 to the purchase price.

So the all-electric i3 is less expensive to buy, has slightly better performance--thanks to its lighter weight--and you'll never have to set foot on a gas-station forecourt again.

The i3 REx costs a little more and you lose some performance. But it doubles the effective range of your vehicle for those few times you may require it.

There is another factor that may put you off the REx though--if you live in California, the i3 REx earns only a supply-limited green carpool lane sticker, rather than the white sticker for pure electric vehicles.

On the other hand, both versions qualify for the full $2,500 purchase rebate from the State of California.

One final thing--according to Moloughney, BMW will be monitoring BEV and REx sales very closely.

Should most customers opt for the 81-mile electric version, BMW will take this as a sign that 81 miles is enough range to meet peoples' needs.

If REx sales are higher, there's a chance BMW's next generation of electric cars will be offered with greater range than it might otherwise have done--since customers clearly want greater range from their i3s.

That's hardly incentive enough to opt for the REx in itself, but if you're a BMW fan and hoping for longer-range electric vehicles in future, it may be one way of making your point to BMW...


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