as said at 5k you're getting bugger all in the power band, mine's been bouncing off the limiter at 7400rpm for the last year at various levels of boost without failure (just dropped limiter to reduce risk to 7200rpm though).
also massive power difference between a t3 (what ever stage) and a T38, it's a bit vague what you are planning IMO.
get forged pistons and steel rods if you're planning for the future, i never looked back on getting the bottom end solid.