Maybe I'm a bit particular, but I wouldn't wear second hand clothes without washing them first and I wouldn't buy a second hand mattress to sleep on. Why would you want to sit in second hand upholstery without laundering it? The PO's body sheddings, spills, and dirt are all captured in the cloth upholstery.
I recently added a 2003 to the fleet and did some seat work - it was fairly easy and straight forward and I don't own hog ring pliers (reused he existing hog rings). Washed the upholstery in the laundry sink with Tide by hand till it rinsed clear - you'll be shocked how dirty the water is after the initial washing and will be glad you cleaned it! Hang it up to dry overnight.
While you have the upholstery off, swap the foam seat bottoms and backs between the 2 front seats - they're identical. The edges facing the doors get the majority of the wear and by swapping them you change the wear point plus the passenger side rarely is as worn as the driver's side so you get the best foam on your side. If you have access to a spare, you might find that using 2 passenger seats to be your best option. I also swapped the metal springs from a passenger donor seat to my driver's seat. It now feels like a new car seat and was well worth the effort to me.
