These actually look pretty good once installed. The Buckles actually fit in the clips, so you could use these to hold a figure in place.

Use a metallic sharpie to color in the metal parts.

I used lace bought at walmart and shoe good them in place. I made them for a Cherokee Hard body, but they should work in anything else.

Print slow without a raft or supports.

You need to print:

4x Seat Belt Tether
2x Front Female Buckle
2 or 3x Rear Female Buckle
4x Male Buckle

To make a full set.