Whether it'a a blower or a turbo, any internal weaknesses (weak valve spring, loose guide, etc) will be magnified by the increased pressure in the engine. One weak plug wire, or a couple plugs gapped wrong that is an annoyance in a normally aspirated car can end up causing a major KAPOW in a blower or turbo application. Make sure you run a boost gauge, the correct timing, correct valve adjustment, valve spring pressures and everything else. The increase in power also increases the build cost and the upkeep cost and time!!!!