the p71s(crown vic cop cars) do have upgraded suspension. besides bracing, shocks/struts, the springs are alot stiffer and have different rates then their big loose boat cousins. They might not be alot faster than the normal crown vics, different years and models vary. but they are a hell of alot easier to make into a nice dd. A little work to the tranny, marauder maf, new intake tube, tune and 3:55s and its not that bad of a car. I loved mine, put thousands of miles on the bitch, and would still chirp second gear like nothing. Plus a 150 shot works nicely with them.