It's a bit of tongue and cheek Russell All iam trying to say is, if i was going for big power i wouldn't go near a standard 2.5L.
As you say, it's only good for 380/380 ish and max 1.5 bar of boost because of the soft ( chocolate bit ) pistons.
A standard newage 2.0L STI has forged pistons as standard and can run more bhp and boost ( more chocolate )
To get a big bhp 2.5L engine you will have to open it up and fit rods/ pistons and liner it so why not start with CDB.
Jac