Nice frameset.
FWIW I've sold four Merckx framesets in the last seven months.
My TSX Century was so tough to let go, but I did.
If yours checks out, you pulled a pretty sweet deal, as I won't let mine go that cheap.
I'm down to two and the only reason one of them is up for grabs is the size.
Campy for the build I'd reckon and an Athena gruppo would look great. A used 10 speed Chorus gruppo would also be very nice.
Have fun!