Twin Turbo/ZZ4 question

[Ummgawa]

I was reading on Bank's site that at 6lbs of boost, a ZZ4 krate motor was an ideal candidate for the twin set up. That particular engine, based on my investigation, has Hyperutectic pistons, pinks (or equivalent) steel crank and stock balancer. Am I missing something here? 12 lbs boost requires Forged, billet Yadda Yadda. but 6 requires minimal metals IYKWIM.

Now I understand the concept on Boost and increased cylender pressure, etc and the need for the hi dollar stuff for the 12 lbs. But the 6 lbs? surprises me that one would suggest the lesser set up at all. Seems to me the engine would be mincemeat if you really drilled the motor for any length of time or even all at once. any thoughts?