I would like to remove the resonator on our 06 Denali. We still have a lot of warranty left. By removing the resonator will this cause any issues down the road with voiding any potential warranty claims ? I am thinking of removing , adding a straigth 18" pipe with a nice chrome or stainless exhaust tip. Thx

No, this will have no affect on your warranty except possibly the fact that the pipe that is connected to the resonator has been altered.