On the data / telemetry topic, here's another easy option for DE days. I've been using a GoPro Hero5 Black with its built in GPS and g-meter for video and data. One click on and off on track, so no fiddling trying to get multiple devices to connect over Bluetooth. And great video quality. For analysis, I use Race Technology data analysis app that's specifically built for the GoPro file format. Let's me compare laps, watch side by side video of two laps in the same corner, play with data traces etc. Analysis is as simple as downloading the session video from GoPro and opening it in the RT application on a laptop.
Sample lap from Portland Int'l last month