Bs.
I've run pretty much stock bottom ends with several turbo setups and never blown anything but a head gasket. It all comes down to having an adequate tune, particularly timing.
I even ran up to a consistent 15 psi on the stock compression ratio and over 20 psi with the lowered c/r setup.
K's are strong as shit, that's why I love them!
On the other hand I have broken a gearbox, but that was more to blame on the welded diff at the time. I now have the k-t50 and still a stock 55 diff (unwelded) and haven't had a single driveline issue in over 4 years running a daily 18 psi!