I've driven both the N/A and the SRT-6 and the 6 did ride quite a bit stiffer than the N/A. When I bought my 6, it rode extremely rough. I checked the pressure in the tires and the dealer I bought it from serviced the tire pressure to 50 psi - the max on the tire. When I serviced them to the recommended pressure, the ride softened quite a bit - but it was still stiffer than any other car I've owned.