I agree that there is a bunch of iffy info.

Let me share my iffy info backed by years of experience.

I ran the TT440 HARD on el cheapo Speed Pro forgings. I never had a piston related failure.

My first build ran through so much detonation that upon disassembly the rings fell out in pieces. The pistons survived.
Some of those adventures included 17 psi boost with an injector spraying water, rubbing alcohol, race fuel, and most any other type fuel I could think of.
The majority of the time I ran it at 8 psi with no injector and the car never had an intercooler.
At one point I surged the turbos over 20 psi and 6,000 rpm without failure. The cylinder temps had to be slightly higher than the surface of the sun but it didn't kill it.

Now that I know better I would never recommend subjecting a set of cheap forged pistons to that kind of abuse but my engine never went to pieces. I did manage to kill a head gasket or two in my time.