Good price for third member or not?

Hey thanks guys, i was thinking he was a little high, but cheaper then some of the new setups i see in the magazines. I havent decided on wether im going with highway gears yet. Im gonna end up going with a 4 speed and want my car to feel good on long straches of highway. How are 3.23s on the open highway? I was thinking the 2.94s would feel sporty enough at slower speeds, but really good on the highway. Im not building a 1/4 mile car, but also dont want it to feel like a slug either.
I guess the 489 case is the case to have, but sense im kinda building a cruiser will a 742 case be ok? If so, sounds like I can pick up one for a little cheaper then what this guys selling his for, what do i need to look for as far hunting down a "good" used third member?