How to rig your Kia Soul EV to be fully drive by wire capable for $500
medium.comDoes this kind of car mods render the vehicle illegal to drive on public roads?
IANAL but dont think so - otherwise all self driving car companies would be illegal :) I would imagine this doesn't make it anymore illegal than modifying your tires/suspension/ECU does. It most likely voids your manufacturer warranty while this thing is hooked up.
Obviously IANAL either. But it appears to me that self driving car companies acquires permits/exempts for their highly modified production vehicles from the state DMVs to be able to drive on the public roads. And most of them have to submit year-end reports [1][2] Geohot's comma.ai (mostly himself) had tried to pull this off in 2016 but no avail.[3]
[1] https://www.theverge.com/2018/4/13/17235788/waymo-permit-ful...
[2] https://qz.com/863718/uber-received-a-stern-letter-from-the-...
[3] https://www.reuters.com/article/us-selfdriving-safety-idUSKC...