Matt is now using 2 GoPro Hero9 Black using the standard GoPro suction mounts. He also uses a GoPro Mic Adapter and Edutigue ETM-008. https://amzn.to/2X2vxaS. If you have 2 people in the car, you can simply use a y-splitter and use two mics. Just clip them to the seat belt in the car.