Stock Magnum rods/pistons durability ?

Since this has been brought back up to the top, I have put a little bit more research in. I have revisited a build that IMM did a couple of years back.( Link below) It really seems like a nice package at a reasonable price. Plenty of power for the street for what I want. The cam may be a little big, but other then that, looks interesting. I may need to call IMM to see how the engine that they built held up. Thoughts?
Build Your Own 455HP Pump-Gas Magnum V8 For Around $4,000! - Hot Rod Network