A smaller turbo spools a lil quicker, and will make the car act more like a BBC, then a turbo'd v6.
One thing to consider with the bigger turbos is that you need to have enough injector to really be able to use it. And the larger injectors take more effort to get CORRECT.
I have a, 4.1L, TA-61, with 60 PPH injectors, stock converter, that is just plan fun to take on trips, ie I rather routinely take 500 mile trips with it. And with a Bst Contlr on the dash, I can back off from stun mode with just a twist of the dial.
And, with something like a 45 on a trip you'd really want an excellent Lock-up converter, IMO. On long hills and grades, and less then flat roads, something like a 911 or Yank really has nicer manners then some of the others, IMO.
I think a 45, with 72s, Translator Plus with an Extreme Extender chip, and a 3,500 stall Yank would be pretty civilized. I've run a combination like this with my WB on it, and it seemed like a real good out of the box combination.