Here's a source worth looking into for OEM NIB belts from various USDM Nissans for CHEAP. This guy bought up tons of OEM Nissan Parts and selection varies week to week, but I scored some great deals on stuff for my B13's and my personal favorite, a $300 NIB NISMO LSD for my one-owner (me) U13. He has a lot of interior stuff but more for B14's than B13's. I just saw a
NIB OEM set of 4 G20 Floor Mats for P10 for $26 plus $16 shipping.
Emgee Parts
He usually has new OEM buckles for the insides, something I would strongly consider replacing if I did this swap. Also replacement seat foam cushions, rear belts for 91/92/93 B13's.
The list of minor sheet on both my B13's plus work I'm doing on my G, truck, is
so long right now IDK if I will get to the belts soon, but this is a
great idea and seeing it in execution, I think a big step up in safety over the crap belt arrangement Nissan sold the NHSTA/DOT on back in the day.