I feel bad for you. Years ago I had an SPAS 12 and really enjoyed shooting it. I used to take it to the local land fill and let it rip on old TVs, refrigerators and so on. One day I even found a large sheet of bullet proof glass that wasn't too badly torn up. Rather, it wasn't too torn up until I emptied a magazine of slugs into it; then it was torn up, for sure.
The one thing that bothered me about the SPAS was all of the parts, especially the small ones. I ended up selling it and buying a Valmet 76 with the proceeds, which I specifically bought for the much simpler design.
Anyway, good luck on the parts hunt.
NRA Endowment & DSC Lifer