For me all new platforms require a lot of sorting and that is why you want a car where millions have been made. The frustrations of finding mechanics, finding parts, and not being stranded is no fun. There are a number of frustrated buyers of Tesla as well as other cars.
Our Replicars, plastic fantastics are NOT PLUG and play... they are like the old Windoze, plug and pray most times for those who are not mechanical and do not know cars or have a sense of how to diagnose an issue.
Many builders have chosen to go with Subie powerplants for ease of finding a mechanic and use a stock ECU, again so that they do not have any issues. A non stock ECU is a custom builders dream and can be made to work well but your comfort zone will increase if you live CLOSE to the builder or ECU programmer.
El Guapo's suggestion of a reasonable cost, simple Acooled is a real worth while solution and cost effective. So is the subie powerplant another platform that many have used and you can find quite a following in Australia in New South Wales for example so choices do exist but personally i could not see any benefits to E-Roadster a car unless your only goal is to stay in the city.