One man's stiff ride is another man's not so stiff. We could get the car up on a rack and conduct all kinds of tests on shocks, springs, suspension travel, etc but in the end it's all in your hands, butt and mind as to how the car feels to you and you alone.
I run 250 and 250 (F/R) GC coil-over springs and a mid setting on the Tokico HTS shocks . The car has TTT LCAs and TC rods and in the back I run Arizona Z Car RCAs. Poly everywhere else, including the steering coupler and ST front and rear sway bars with 245/45/16s all around w/2 degrees of negative camber. Roll bar with added cross brace for shoulder harness and triangular front strut brace. And of course BDP frame rails.
Were the coil-overs worth the price. For me, absolutely. My Z, my ride. The next owner can always put in softer springs and dial back the shocks, replace some of the poly and run the car at a higher stance. The ability to make adjustments to me was critical.
Stiff? Yes. The race car has 400# springs, a higher shock setting and a full cage but basically the same set-up save for the LCAs as they are stock in keeping with the rules. Stiffer than the street 240? Yes.
One of the fastest drivers I know had a 240 that I wouldn't drive to get milk in as it was so loose I feared the rear end would come around if I blinked. Having been under the car assisting with some needed repairs, I doubted whether it would pass an actual road-worthy inspection (ball joints, tie rods, worn bushings, etc.) but was he ever so fast in it.