Like ncollins said. They are luck of the draw. Some stock bottom ends live at 800hp with no issues and some trucks don't last more than 500 miles on a tuner. It's basically luck lol
I beat my truck all day long, I drag race it and I have done a number of sled pulls and I never had a issue. And since I studded it I have no worries. I'm actually making a 2000 miles trip hauling a trailer with my truck and I'm not even worried about anything on the truck. Just keep up on maintenance with them. I have my truck since 53k and tuned and deleted it with in the first tank of fuel, then studded it at 75k and now I'm at 114k.