I had 215/16/60's on my car. I Upgraded to some American Racing Torque Thrust 2's with some Kumo's 245/17/45. I am all over the road now, Almost not sure if the 1400 was worth it. Car looks good but its hard to drive now.

 

I had a simular problem when i stepped up from 245's to 255's and that not even a big difference. The wider tire follows the road more because it cannot sit inbetween grooves it rides ontop of them and follows the road flaws more noticeably. Another thing you might want to try fixing is your idler arm.