I cannot comment on the mapping, I know the tuner who wrote the map. I think the point he was trying to make was he was trying to map around the audiable surge point of the ko4 with a high flowing engine setup, it's a big job to set the ko3 maps to run with the ko4 and even more so when trying to eliminate the audiable surge point. A lot of the ko4 conversions I have seen most have not had the surge worked on, they give nice smooth graphs but flutter like mad.
The torque on the graph on page 1 is basically running with the boost being held back with fluctuations from the ecu PID controllers trying to keep the boost lower than the turbo natural spool profile.
I have ran a BWA engine to the max with a k04 setup, 404bhp 400lbft and the rods held up solid but the rings let go first, same with Dans Leon running a GT series also spat a ring before a rod.
Rods snap when they want to from, silly high peak cylinder pressures from high boost and torque, casting imperfections, continued elevated engine and oil temp, (the reason track days kill more engine than A road driving)
IMO it would be hard to kill a BWA engine with mapping, unless it was set to spike the boost at 30+psi