Yeah, the crank and connecting rods are forged on the M42 and they are pretty beefy and overbuilt in my opinion. Just about everything on the M42 is like twice as heavy and strong as it needs to be.
Guess which one is from an E30 318is, a diesel E46 320i, Euro M3, and an E36 318is?

from Gizmo's S42 thread on bimmerforums
Well obviously the really beefy one is from the diesel cause of the crazy compression ratios they run. Far right is from an S50 (320hp euro M3), far left is from an M42, and the last is from an M44. Mind you, the one from the M44 is not forged and handles 140hp perfectly fine.