Not in my experience, I've had PS4S before Falken. The ride on PS4S is stiffer.The indy sidewall is about the same as ps4s. I had both.
EDIT: I felt I should be more clear. While the ride on the PS4S is as stiff as the FK510, the FK510 sidewall is still stiffer than PS4S. FK510 > PS4S > Indy 500 in terms of "feel" , not ride quality, in my observation.