This is a nice collection of 2001 MS69 WTC coins, you would only need the $50 gold coin for a very nice MS69 set of WTC coins. The WTC 2001 $50 gold coin would probably set you back another $5000-$6000 but still.
This set of 4 coins are up on Ebay for $3,950 and I think its a good price. Auction link