Well, rear squat isn't necessarily a bad thing...but if your car wants to push on power on corner exit then yea, you want to limit the amount of rear squat.
Elff, for street I liked the Z0K bars front and rear but with Autocross, the softer front end definitely is nicer. Like I said, if I went with the 6k front springs I'd be golden with the current setup. The softer bar up front gave me a lot more bite on turn in but the softer front springs kept too much weight up front mid corner and corner exit limiting how quick I could get back on power without the rear end breaking loose. I was able to dial this out with the damping but it would be nice to have a bit finer bit of adjustment by not maxing out the damper settings to get the car neutral.