What trans should I run?

I voted buy it all.
The price isn't all that bad and you will have a complete set up to install in the future if you wish.
I would go through the trans and at least reseal it before using it and buy a new clutch and rebuild kit for the linkage unless you luck out and everything is really good.
You will never go wrong getting a complete set up from a car all at once.
Just my 2 cents.