Thinking about getting a Corsa exhuast system and Volant cold air intake, but will this void out my warrranty in any way from cadillac?? I have an 06 STS4 V8 w/ certified preowned 6yr 100K.

Not usually.

Corsa exhaust used to be endorsed by Cadillac... the air intake could easily be swapped back to stock for warranty work

If you replace the mufflers, you will only void the warranty on the mufflers.
Do it and have fun!

As long as the accessory(s) are not the cause of a particular problem then they do not automatically void any warranty service. Corsa was the "official" GM accessory and although not mentioned by name is still provided by individual GM dealers as an official accessory.

I have both and although I had a small issue this past week with Techline using my CAI as an excuse for a different problem, in the end they agreed and covered everything under warranty.