I'm really having trouble deciding the srping rates I should go with...

I'm planning to have a streetable/track setup (more leaning to street!) of 6F/4.7R

I've heard 6/4 is a good setup, any ideas? 8F/6R is good I also read but is near the limit to street driving. Where i'm from the roads are absolutely shit house anyways.

So what are your rates?