A good Donkeycar option for smaller tracks
If you’re looking for a car that’s a bit smaller and easier to handle than the Exceed Magnet for Donkeycar, the 1:18th scale LaTrax Rally (https://amzn.to/45jWFDD) is great. Brushed motor, easy to add a third RC channel as an e-stop and fits the RP5 with the RC hat perfectly. You can use the RC it comes with, with no need for an I2C servo board or gamepad controller with limited range.
I designed a 3D-printable mount that fits the Pi and camera. Download it here.
If you want to add a third channel as an e-stop, you can follow the instructions here (scroll to bottom)