I've went thru ALL of the links you've posted and it only answered 1 question of mine (no.2).
My mechanic, tuner and myself need to know the remaining questions to decide whether
this would be something worth the $$, effort & time, and where i'm at, there's no RB30 block at the wreckers,
and even if there is, we cant get it registered (legalized) because of the Cc difference from the RB20.
So please guys, help me if you can. Thanks.