Most folks that go with a high end shocks also install a height-adjustable spring perches. They also spec the spring rate and length that they use.
FWIW, I have JRZ RS1 shocks and Swift springs on height adjustable perches and like them alot. I've also run Konis and ASTs on other cars.
In terms of the differences in shocks, google terms like "hysteresis" and "shock dynamometer" and you'll start to get a sense of the issues.