Motors

 For my Fiat 500 which weights around 500 Kg it would be enough a 10-15 Kw engine.

Size need to fit the small rear engine bay.

The motors I've seen used for similar projects are:

Agnini 135 - 13Kw

Curtis AC20 

Mahle 14Kw

Motenergy

Z-Force 

Siemens (too powerful motors for my application)

Green motor tech (too heavy)

Shinegle

Unidriving System

QS motor

Maiden EV motors

Mars motors 

Direct Drive 

Engiro

I am inclined to go for an AC motor, but there are good options also in DC or OEM motors.

Pros and cons of the 3 motor options

AC motors

• inverter
• regenerative
• is cooler 
• is lighter
• low voltage 3phase

DC motors

• controller
• high torque low cost
• usually get hotter than AC

OEM motors

• high voltage >280
• efficient
• smaller cabling

My choice is for now a Motenergy ME1507  (14,5Kw - 92% efficiency, Peak stall torque 134Nm, Recommended max rotor speed 6000RPM)