I go to UTI in Exton, PA and we have this kit @ school.

We had this kit on an 05 Pontiac GT slOw. with the 6.0L block. There is a dyno @ school. The instructors installed it during an open house for parents students, and future students to see. The car was totally disassembled beforehand to allow the install in one day. That block ended up being toast. Don't think is was any errors in assembly or mfg. They ran runs @ something like 4psi and raised it in incrememnts. From what I heard the block "developed it's gaping hole alongside cylinders 2 and 4" in the area of 10 to 13psi. not even one atmosphere!! The power put down was in the area of 600 if I'm not mistakes. This GTO since then has a new block and no STS turbo kit on it.