I would assume that you are speaking of static compression numbers in relation to forced induction. The lower the static compression the less likely the motor is to detonate, but will normally make less horsepower at the same boost/jet size that a higher compression motor will make. Higher compression forced motors tend to need a little more care when tuning as well, that is why you see most people dropping compression thinking that it is the best way to go. Most people don't have the ability or knowledge to properly tune a higher compression forced engine.