Unless you've done something to improve on the factory design, that's really just your opinion. The "sloppy feel" is built into the steering of every pre-'03 Crown Vic. :-)
Mind you, it only feels sloppy. It's accurate, it doesn't have any play in it, but it doesn't have a good "on-center" feel to it. The rack-and-pinion steering in the new ones is unquestionably better.
Still, like your '95, my '97 with is just fine with high speeds. The factory-optional handling package makes the twisties fun, too. Some people are surprised to see a Crown Vic take curves and freeway ramps at double the posted limit.
My definition of slop is the flat center - no reaction for a given input. Mine gives perfect response for the input. Having driven dirt race cars and dump trucks, dozers & excavators, BMW's, formaul ford, 250cc shifter karts (my 100% absolute all time favorite kick in the ass!) and whatever else, to me, it's all about response, not an on-center "feel".
A r&p setup would be better. Regardless, I regularly run 80ish (average for Connecticut), a 20 mph increase would be negligible as long as the differential between me & my fellow motorists remained proportional.