If you don't wear you're seatbelt you are definitely increasing your chances of injury. Only 1 in 300 accidents were impacted negatively by seatbelt usage, so the odds are certainly in your favor. One thing of note is that at an impact of around 80 miles an hour, neither seat belt or airbag will do you much good. At that speed your organs slam forward internally with such force that you're pretty much a goner. Threshold braking involves locking up the wheels releasing only briefly to allow steering.
Threshold braking allows shorter stopping distance, but ABS requires less skill.
HCSO's pursuit policy is fairly liberal, but they have numerous checks and balances. Chases are closely monitored by the supervisor, specifically the reason for pursuit, speeds, and environment. My opinion on it is I don't think I would pursue for property crimes, only for crimes against a person. I have the same opinion on using deadly force, both for law enforcement and civilian. I would never consider deadly force on or off duty for a property crime.