I have a 2001 mustang gt all stock engine with close to 100xxx miles and I want to add a V-3 vortech supercharger system but I don't know if it would destroy my engine or if I could hold together
Generally a stock GT can hold up to 425 HP....not that I would push it to that edge. If it is stock (260 HP at the crank) you can boost about 140HP and be OK provided the car is in good mechanical condition and you get it tuned after the install. Without looking up what the V-3 would add you can base your decision on this.
I added cams to my old GT at 150K and never had an issue. It had 235K on it when it lost body integrity by hitting a tree. The engine still ran strong.