2002 Mitsubishi Lancer Car shakes when accelerate and thump

I have a 02 Lancer OZ-Rally and When I turn left I feel and hear a hard thumping sound and when I drive on the highway and accelerate over 60mph it vibrates but when i let off the gas and coast, it goes away. Mitsubishi balanced all my tires (which are new) and checked tie rods and ball joints, all ok. I just changed the rotors and pads also. WHat could be the reason for the thumping and vibration.