high-rev chips, good points vs. bad points

I have a 1999 z28 camaro. When I bought it, the mechanic told me he just got done installing a high-rev chip. I don't know anything about what he put in, or how it works, so I came to these forums to get these questions answered.

What does it do? Where does it go? How much do they cost? Why doesn't everybody have one? Are there any downsides to them? <insert related question>?

There is no "chip" in an LS1 PCM... you need to "reprogram" using software that reflashes the fixed chip, or you need a hardware "programmer" that connects to the ALDL connector and reflashes the program in the PCM. A "high-rev" chip doesn't really explain much, without knowing the specifics of what was changed. He might have simply raised the pre-programmed rev limiter. No big deal.

Increaing the rev limit doesn't really accomplish much unless you have the cam and heads to support the higher revs.

sounds like :bs: to me....

contact him for more specific description...could have been something like a handheld programmer.