dependability with tunes
i have friends with diesels (1-00 ford F350 with a DP, 3 dodge boys. 2 with juice, one with a superchips programer).
after tuning, all 4 have had some sort of trouble. Ford, shifting problems. dodge, trans problems and one of the dodges actually burned out the computer while loading his superchip tune, (luckily the dealer cover'd it or it would have been a $1,500+ bill). granted these troubles may all have been a coincidence and everything depends on the way someone drives.
in your honest opinions (and expertise) do tuners (if used responsibly) reduce the longevity of motor, trans, injectors, hpop or ?
one of the reasons i'm asking is because many who have posted a question about tuning, throw in some type of statement wanting to keep dependability and longevity.
why, if it doesn't affect the trucks, don't the manufacturers 'crank' up the performance from the factory?