IMO comp ratio affects how powerful it is off boost, but not hugely how soon the boost comes in, a bit, but not as much as other factors.

If you want big power n little lag then low comp n big boost with clever cam/head specs is a better bet i reckon. dont have to go hugely low anyhow if you wanting about 600bhp, Rod running 7.2:1 i think.

What fuel can u get cheap? If its high octane then you can get away with higher comp too.

Also beware of people claiming they running high comp when infact they bullshitting to sound good