but that is why I made some middle of the road rate springs for my car. My coil-overs are BC Racing and with the adjusters set 3 clicks from the lightest setting (they only control droop rate) my car rides about the same as a stock TT on "sport" setting. I do think a lot of the ride quality or lack thereof comes from the valving inside the shocks.
Here's another spreadsheet with the BC Racing heavy rate springs overlaid to show how they would be setup and compare with the stock and custom springs. This gives a good example of the additional load required for the same amount of travel from each setup. Note the much higher loads at maximum bump. Another interesting note on the rear BC springs, they only had 4.5" of travel capability while their shock had 5.3"... kinda miss-matched IMO.