2.5" is fine (if your wife can live with 2.5" so can you)
If you can find a cheap used 4bbl intake and carb.. then yes...
it's all your budget so for you to decide.. pistons? if they are good don't change them.. if you want to re-ring/bearing that's pretty cheap.. if you heard the motor run, personally i would cam/intake and drive it. (i'm reusing a good used bottom end for my temp build right now)
Whatever you figure for your budget, double it.... little pieces will $20 you to death.