185-60-15's..... NO GOOD OPTIONS!!!

[Loren]

You could (should) start a new thread.

Everything is relative. "Softer" than what? "Harder" than what? The spring rate is probably going to be a little stiffer than stock, particularly in the front. The harshness in ride quality is going to come from lowering the car 2" and not making the springs stiff enough, as is the usual case.

If your goal is to make a stock xD ride SOFTER than stock, you don't want to lower the car at all, nor do you want to fit any aftermarket springs. I'd look at the tires. A nice cushy set of touring tires with pressures set on the low side (28-30 psi) will do wonders for ride quality... at the expense of everything else.