Hummm. It seems as though an engine swap would require quite a bit of tuning. The front wheels are powered by a small gas engine but each rear wheel has an electric motor powering it. So, in essence, it's AWD is actually a FWD, Left-RWD, and right-RWD. Changing stuff up front might mean altering each part of the rear.
It seems mildly absurd to swap an engine into a car that is designed for fuel efficiency rather than sport. I suppose if you are dead set on the looks it's not so bad, but just seems odd...like shoehorning a 427 into a Geo Metro.
But, to each his own.
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"Ferrari isn't a car, it's a lifestyle"
-Enzo Ferrari.