The spring rate you can get away with using on the front will depend how far you lower the car, without bottoming out. If you lower a lot, you need harder springs, than if you lower a little..
I went for a very minor lowering (1"), so the 9/12 spring rates were harder than I needed. I ordered replacement springs, and things are pretty decent now. I am using softer springs than mentioned above. I am using 9kgs on the rear, but am using airbags to supplement this, and raise/lower the rear of the car for loading. I'm still working on the best option for the front.
Don't forget that if you go for softer springs, you might want to allow for more spring travel/longer spring.
ie: if you have a 20cm long 9kg spring, and want to go to 7kg, you *might* need to go to a 25cm long spring to avoid bottoming out.
Those of you slamming; just want cast iron girders :)
Cheers,
Scott.

I didn't see an extreme drop option, so is that what the guy from the 20x11 thread went with.to get that low?

I realize this thread is from 2014, but I am wondering if you have an update on the extreme low kit install and pictures...

I am torn between the regular kit and the extreme low and I cant find pictures of the extreme kit installed on an E53