He will be getting no where near 450rwhp with a stock turbo.Lucky to get 300rwhp.And correct me if im wrong but didnt the 34 neo come with GTR conrods?
Saying that go for the forged pistons,later down the track you might wont more power(ECU,exhaust,boost,bigger turbo)
With forged pistons and a good tune i cant see why that motor combo wont achieve mid 300s without blowing something up.
But im thinking waaaaaaay into the future. Ive said before in a previous thread figure out what you want from the car,then put you wallet on the table and see what you can afford.
EDIT: Is there a legitimate reason for a rebuild? eg: rings gone,spun bearing? If not leave it alone and spend your cash on the basics.