The Car: For this project the relevant parts are that it's an E46 with Nissan VQ37 engine swap (running OEM ECM) and Alpine head unit. I need to interface with both of these things with the steering wheel controls, and neither of them speak BMW. The Plan: Make custom PCB's to replace the OEM units which will interface natively with the headunit and ECM respectively. Complete OEM look and feel but otherwise totally bespoke. Will likely use an Arduino for the radio controls, hopeful