MANY thousands of people- including myself- have run a blower and/or Nitrous with stock bottom ends with no problems. I've run 10# of boost and also have run 125 shots. The keys are
1. good tune
2. good head gakets and ARP hardware
3. good supporting parts- injectors, fuel pump, etc.
Vortech, Procharger and most Nitrous companies all sell entry level kits that are plug and play with no tune needed. With power adders, you can run rich all day long but only lean once. The horror stories you hear are about guys who slap on a power adder and make no or incorrect adjustments to timing and fuel. Guys start swapping smaller pulleys to up boost, or change jets on Nitrous seeking more and more power. As long as the A/F ratio is within specs and you have a tune which will keep the timing and fuel curves within safe levels, there is no reason to worry.