If you want to dish out the money for the Koni Yellow/GC setup, I guarantee you will not be disappointed, regardless of the spring rate you choose. A lower spring rate will allow a wider range of stiffness adjustability on the Koni Yellows. With a higher rate, you must run the shocks almost full stiff to avoid bouncing around like crazy.

For a lower cost alternative to the Ground Controls if you don't necessarily want or need the ride height adjustability or custom spring rates is pairing a set of Type R springs on the Koni Yellows instead. You could pick up a used set of springs for less than $100 and it will offer a subtle drop that could be adjusted to around 1" just messing with the spring perches on the Koni's.

Here is a DIY walkthrough in which he is using ITR springs on a set of Koni Yellows. You can also get a sense for how the perches work if you wanted to go that route.