cd player installation ?

[Marcoz]

my factory monsoon cd player took a dump on me and will not play any cd's, says "error", so i bought me an after market jvc cd player along with the installation mounting kit from best buy. My cousin said that he had to also buy a harness from wal mart because of an amp that the factory had behind the dash, that was in his mustang, my brother told me the samething but with his pontiac, do you guys know if my camaro would need this "harness" or not?
thanks