In the car that has its' interior complete, I noticed it only has lap belts. I'm a huge "safety first" guy with belts. I won't leave my driveway without a 3 point belt on. Heck, I work in the auto insurance claims business, I've seen waaaay too many nasty results of no seat belts. I know...these cars aren't bank vaults when it comes to crash safety anyway, but a proper belt certainly helps. In the years 4BC (before children) to 1AD (after delivery)

Has anyone put in 3 point belts in their cars, or a 4/5 point safety harness? Is it something easy to do? If I ever get one of these cars drivable, or buy one already in driving condition, I'd want to be fully belted in.