I just read a quick thread on comp d, and that is what it said, however it had no mention of the turbo's used. I was lead to believe that the owner of the truck was the one that posted those specs about the hypermax rods and low compression pistons. The two stages of nitrous was posted previous to that, by another user but was never disputed.
I know in the dmax much over 550hp and you are living on the edge of the rods. 1200hp+ has been made on a stock 12v cummins bottom end, but guys have also bent them at ~900hp, typically guys start to think about milling out pistons, and billet rods around the 800hp area.