1. plate number
2. take picture (of the goons and the mc)
good quality dashcam (my old dvrs that I bought for less than 1k are intermittently hanging, and not recording at all), so I'm saving up for the Thinkware brands.
I think the dashcam will help with the 2 items you mentioned. In the heat of the moment, you'd sometimes forget to take down these details and take good pix since your adrenalin is pumping.