The easiest (and free) way to soften the ride is to drop the tire pressure. Like everything else pressure is a compromise. Lower pressure will slightly decrease fuel mileage and tire life, lessen cornering grip and steering precision, and allow a leak to get you into trouble/danger quicker. That said, if I really wanted a softer ride, I would personally have no qualms about going down to about 28 psi. The next really practical step is to trade for a Grand Marquis. The last directionally workable approach would be to install OEM Motorcraft base Grand Marquis or, softer still, Town Car shocks--they all physically interchange. Unless you are really good with wrenches, considering cost, hassle, shop risk, and the fact that you are playing development engineer, the Grand Marquis trade is a better solution.