Aftermarket Cans and Power Commander?

[ChemoDave]

Do you really need a PC, I have been reading so much on the American.org site that Im cunfused.

Im not looking for more HP. Just more noise,etc. Will it harm anything engine wise if I just run it without a PC?

Its a slip-on system (mid-pipes and exhuast from the pegs back).

Has anyone left it running on the stock ECU?