It's actually more like 7.6:1 on an un-skimmed head with C20LET's...

I wouldn't worry too much about response.. it's great with a suitable turbo (et, T34)..

The black top rods are much longer, to the point where you'd most likely get positive deck protrusion with these pistons. I'm not sure i'd want to ream out those rods by 2mm either.