2005 GTO Do I need canned or custom tune?

[ja55nc]

I purchased a 2005 GTO with a bad motor. It had a custom tune in it of which I cannot get any info about. I just installed a new LS2 motor and have added the following mods..Livernois stage 1 cam, long tube headers, cold air intake and stall converter. I am new to computer cars and need to know if a canned tune will work or will all the mods call for a custom tune? Without knowing anything about the tune that is in it, is it ok to start the car with the tune that is installed or should I retune before start up? I have not purchased a tuner yet and am confused about custom tunes. Do you purchase a tuner, then buy custom tunes to download to it? Where can you purchase reliable and tested custom tunes? I know this is all dumb questions for most but I am from the carburated era and want to do this right..Thanks

[mikel]

You'll need a custom tune for sure. Check the dealer locator for a GM CMR tuner in your area.