The screech you mention, just for some comparison:
I had a screech/squeal that happened under heavy load, sounded like a belt slipping. Sounded so much like it that even the dealership thought that was what it was, but made no sense that it only happened under load at higher RPMs.
Long story short, the IC to TB inlet had torn and would leak only at higher loads/4k+ rpm -- but screeched/squealed like a belt. So consider what conditions it happens under as much as you do the sound it makes.