Mine blew up because of my ignorance in the tuning part. I was doing things I had no business doing lol.. It probably would have blown up even if it was tuned right... some of the other guys were tuned correctly and blew up anyways.. acex, luv2drag, boosted5, 05_quick4door (i think blew up too) to name a few, these engines just don't take it well unless you build them.. take a look at acex's build http://www.355nation.net/forum/projects-build/46371-introductions-sorts-forged-turboed-3-5l.html
There were a lot of other variables that led to detonated motors though, generalizing and saying that you will blow it up is not right if the set-up is thought out well enough. Or if you're motor is already tired and worn out before you put boost to it, it will go bang. I've been running 7psi centrifugal supercharger for almost a year now and my motor runs just fine, starts first key turn, and burns no oil.
If you push the boost and timing too far, yes you will have a bad motor in no time. If you stay under 10psi make sure you have plenty of fuel and keep the timing mild, it will last just fine.