I recently posted about this in a Sur Ron Facebook group.
Basically, the motor will be pretty cheap, like 300$ excl tax/shipping.
The only but biggest issue is that it will only come as encoder version (no longer hall based sensors), meaning that you´d need an inverter that support encoder position tracking. To my knowledge, the most common 3rd party inverters for Sur Ron like ASI or NUC do not support that feature, so you´d have to buy smth like a fardriver controller with encoder support..or get really complex and install a sevcon.