Dc34v6

I just bought a 98 c5 vette. It has long tube headers x pipe and axelback and air pump was deleted and tuned out along with skip ship shift tuned out and fan speed has been tuned but i dont know if fuel or spark was tuned. My question is. If i were to plug in my diablo sport intune and adjust or modify the tune on the car would it back up the custom tune that is on car so i could return to custome tune later. Also if i install a diablo canned tune. would it back up the custom tune that is on the car? Then i can reinstall the custome tune to where it was before i installed canned tune? I am not shure where the car was tuned or what all was ajusted. And i dont know if it was a dyno tune or if they just did a few adjustments for air pump fans etc. I mostly just want to adjust fuel trims for my altitude and data log for spark knock etc cause what if its tuned for higher octane 91-93 octane and id like to know if i can run 87-91 safely lol but im afraid my tuner miight erase or not save custom tune. I know it will backup a factry tune to reinstall later and release licenc but not shure on cutome tune. Im afraid to plug in my diablo tuner because of this.lol