Location not withstanding..I sold one of those back in the spring for $600. Fresh top-end...ran like a champ.
Now add to that the huge shopping list your buddy put into it..no question in my mind your buddy isn't coming out of the machine ahead at his asking price.
You told him he's crazy, I hope he wasn't insulted..he knows what it cost him to do all that work.
$800 sounds fair to me!
Current toys..
1986 Honda 350X..trail bomb!
1985 Honda 250SX..my main mudder
1985 Honda 250ES..Back in Black Trike
Current non-trike toys:
1990 Honda TRX300FW
1995 Seadoo GTX
1998 Polaris Indy Lite 340(Nearly new looking)
1998 Polaris Touring 500
1998 Club Car (electric)