This is going to be a long post, so fair warning…
To answer your question I think you first need to ask yourself a few questions:
1) Do you have anything else in your life that you want to take rugged video of?
2) How much information do you want to have in your track videos
3) How much editing are you willing to do to make the videos come out the way you want?
If all you ever expect yourself to want to do is track videos, then some of the dedicated track recording systems mentioned by others above are probably the way to go. If you are like me, and probably a lot of other people who aren’t racing competitively and are just out for a good time, then your better bet is probably something more along the lines of a GoPro/Garmin rig.
I personally run the following equipment:
-- Garmin Virb Ultra 30 w/ Bluetooth OBDII dongle – mounted on the hood with a GoPro suction mount
-- GoPro Hero4 Silver – mounted on the rear with a GoPro suction mount
-- GoPro Hero4 Black (loaner from a friend) w/ external mic adaptor and Olympus Stereo Mic – mounted either to a stick-on mount on the center console or with a GoPro suction mount on the inside of the windshield
For video editing I use the following:
-- Garmin Virb Edit software to pre-render the front Garmin camera and add all of my gauge and GPS data
-- Cyberlink PowerDirector editing software to piece together the 3 cameras, create the picture-in-picture layout, and mute the 2 external cameras
A couple example videos from my setup (from my Z, not my R):
Autocross:
https://youtu.be/qpJnUVl6kec
HPDE:
https://youtu.be/TtLXnuTSXmA
Equipment reviews:
-- As far as my equipment goes, I can’t speak highly enough of the GoPro suction mounts. I’ve been north of 130mph and they have been rock solid (but I do use some 3mm high-tensile cord from a climbing shop to make tethers just in case). GoPro’s mounts in general are very good including the rollbar, the handlebar (which works on head rest posts), and the stick-ons. One thing I highly recommend is getting one of the thumbscrew wrenches to make sure things don’t move/vibrate at speed
-- GoPro – My experience has been nothing but positive with GoPro. Their remote is awesome and can power multiple cameras on/off and gives you a visual indication of how many cameras are connected and what the cameras are doing. I think the picture quality, on the Hero4 at least, is better than my Garmin Ultra 30, especially in lower light. The touch screen on my 4 Silver has always worked well and I do get good battery life out of the camera. My Hero4 case system has been more robust and easier to deal with than the Garmin’s and I don’t have the issues with lens fogging that I do with my Garmin.
-- Garmin – The feature set on the Garmin Virb Ultra 30 with the built-in GPS, ability to tie into a Bluetooth OBDII dongle, ability to add in a heart rate monitor if you have the right type, the image stabilization, and the ability to use all of GoPro’s mounts made it too tempting to pass up. I think GoPro’s newest cameras have some of those features now but I haven’t gotten to test them. Garmin’s remote is absolute garbage compared to the GoPro one and I have had many instances of lost video because the remote un-paired itself. Garmin’s editing software is also better than GoPro’s and the process of adding gages is very easy. One thing that Garmin claims but I haven’t been able to verify, is that if you use multiple Ultra 30s, you can sync them using the GPS timestamp which would be very handy.
I’ll cut myself off here and if you or anyone else has any questions or wants any information/opinions I’ll be glad to give them.