I've just done this (drivers side was frayed beyond repair) and mine had side airbags. You can tell if yours does because you should have a sticker on side of the car saying Side Impact Protection, and another sticker in the drivers door recess). When i removed the 19mm nut at the bottom (behind the sill) holding the seatbelt retractor, there is also a side impact sensor bracket attached to the same nut! So when you remove the nut, you will also remove that sensor and it has a pin pushing against the sill, which would extend when removing nut/retractor...hence air bag might deploy (i don't know how it works - maybe its a G Force sensor?). To avoid that happening, using the above procedure, add step 1; disconnect the car battery, and leave the car for 30 mins before starting the job.
As always, It's simple once you've done it once. But it took me about 2 hours initially, going carefully because i didn't want to damage clips since car is old, and brittle plastic, and hard to get replacements these days. In the end i did damage one of the clips at bottom of the plastic 'corner casing'?! that goes under the seat, attaching to the long sill plastic. I also threaded 2 of the many screws holding the sill down. I used threadlock on them to fix that.
The seat belt kit (Seat Safe) came with loads of replacement screws. I didn't need to use them, except at the top where the replacement seatbelt design had a different top mount.
The original belt that i was replacing; all the nuts/screws came out easily using a short breaker bar/ratchet. No thread lock detected on the originals.
