Quote Originally Posted by RX4BRDM
Lowering compression simply gives the tuner a larger window to tune without detonation.
With higher compression you can attain a higher hp number with lower boost, but you run the risk of detonation/preignition.
If you lower the compression you will need a few more psi to get to the same spot but can also turn the boost up alot higher.

I have a couple of boosted cars my favorite is on 12.5:1 compression but only drinks race gas so detonation isn't an issue.
What motor is that?? Most B series cylinder walls will not take it for very long.