The basic components we will need are a motor, controller, charger , batteries, throttle assembly and DC to DC converter.
Soliton JR from evnitics.
Synkromotive controller http://www.synkromotive.com/DCControllers.htm
Here is a successfully converted Honda civic parts / spec list. I like most of this parts list since they used parts closely following the parts selection used by manufactures building vehicles for everyday use.
In my opinion one of the most successful electric vehicles is the 2002 Toyota RAV 4. They come up for sale every now and then out of California mostly where they were originally sold. I have seen a few for sale with 100K to 150K miles on them, they have been used as everyday drivers for over 10 years now. What better testing is there? Some common things I have noticed are AC motors running higher voltages around 300. Then of course there is the top secret battery pack and BMS.