lower compression means the engine has a lower detonation pressure, and is less likely to do damage in the event that it detonates. You also have to run a lot more timing to get the power out. Higher compression means you're more liekly to detonate, have a higher detonation pressure, but will make more power per psi, and have a faster spool time most likely.


The reason that VTEC is said to not be good on turbo engines is that on the DOHC vtec engines, there is more overlap on the exhaust cam. Exhaust overlap on a turbo means you're blowing some compressed air straight out the other side of the engine.