I have ordered a Turbo Back Exhaust. I need to know if the factory computer can be programmed for this or do i have to buy a new Programmer. Also i know you should change the tune when installing but i might wait until after i install Blow Off Valve.
Now as for your question we need a bit more info in order to make an informed answer.
Will your turbo-back exhaust system be catted, or will it be an O/R type?
Do you currently own a programmer for your car? You state you may need to buy a "new" programmer. That leads me to believe you currently have an "old" programmer? Is this correct?
Bottom line is this... if you are replacing the exhaust from the turbo back you will need to have your stock computer reprogrammed in order to keep the tune safe and take advantage of the increased exhaust flow. I would not drive the car around with a performance turbo-back exhaust without getting it tuned to ensure your A/F ratios are safe.