Talking with the guys in our engine development/build department, the OEM engine looks as though it should handle 500 or so HP without issue. Like other modular engines, the connecting rods would probably be the first weak link, followed by the pistons. The crankshaft, while cast, seems pretty robust and looks like it would handle quite a bit more horsepower than that. The valvetrain also looks pretty solid and would only require some basic upgrades to make it more capable.
Thank you,
Rick