Adding Headrests

My thoughts as a traffic safety research specialist:

If you are doing this for safety and not for cosmetics—and I wholeheartedly endorse this effort to improve the safety of the car—then forget any of the Mopar head restraints (they're not head "rests"). All of them are far too low to do anything but worsen your likelihood of whiplash or worse. When you are struck from behind, your position shifts and your spine extends such that your head rises significantly from its at-rest position. That puts any of the original Mopar head restraints right at your neck, serving as a nice fulcrum over which for your neck to bend rearward. This is definitely not what you want! If you're going to the trouble of adding head restraints, put in ones that will actually do some good. My top recommendation would be to get the ones from a Volvo 240. Not only are they tall enough do a very good job preventing (or at least reducing the severity of) whiplash, but they are also see-through so they don't block your rearward visibility, and they're also quite comfortable. They're vinyl-covered so you can spray dye them to match your interior (see here). Installation wouldn't be difficult if the seat were already taken apart; you'd just need to weld some brackets to the seatback frame.

As for proper seatbelts: Yes, but pick carefully. See this post (and links off of it).