my uncle is a cop (seriously) and he said the suspension on the interceptor crown vic bears no resemblance to the stiffest suspension you could get on the civilian model, which he has as his DD. so i imagine this is equally well set up, and not be the big rolling sedan that it is based off of.
LAPD chases. they need fast cars.
plus they need the speed when responding to calls with full lights and sirens. they can average 100-120+ down the freeway. the speed is not just for pursuits.