This has been covered. A lot. do a search.
Iron block = stronger
I4 = better spool
aluminum block, even semiclosed, isn't as strong
H4 = LONG exhaust path to turbo as well as for IC
More displacement is nice.
But if you are going to build something.... either way its gonna be a built motor, so who cares about stock anything. STi tranny is better, other drivetrain parts are a wash.
Buy what looks better.