The tear in the replacement woofer I bought is very tiny, so I think I can fix it with very minimal materials. They're rubber surrounds also, so I should be able to make the seam invisible. My thinking is I don't want to use any heavy materials or globs of caulk for the patch that would change the way the speaker moves. If it was foam I'd consider replacing, but again, I'd have to get surrounds with the exact same qualities for it to sound the same wouldn't I?
*Edit: I just realized you meant filling in the nicks and marks on the cabinets! Lol, duh. That's actually not a bad idea at all.