Salvage is a huge RED FLAG.
Anything with a Salvage title will have a value below KBB fair. It might be a decent deal at 8-9k, but don't go over that. The salvage title trashes the resale value because you don't know about lingering damage issues.
My hunch is that you're best off just walking away. If the seller is asking $11k for a salvage, I doubt he's likely to come down to a fair price.