What are your tire pressures? Start with the recommended pressures there is a pressure sticker in the door area (I can't remember which door exactly). Lower the pressure a little and try it. Did it ride hard before you got the Goodyear tires? Sometimes the tire shop puts 40 psi in the new tires which will hurt...My 1998 Mystique has the original struts at 80kmiles, and are still good, firm ride (205/60-15 Bridgestone RE910) but not tiresome. My sister's Mystique has 114 kmiles, rides good too on old struts. Worn out struts make the car wallow or shudder, but not usually a hard ride. I put Sensatracs and front springs on my 1985 Dodge Lancer, ride damping was firmed up from its worn out struts, but not harder impact than stock. I find the Mystiques ride well, stiffer than my Dad's Avalon, smoother than my 1991 SHO which hits the bumps hard...