i got the Falken Ziex 512's... i got 205/ 40/ 17's..... now, they're M/S rated, so i think the tall tread is bending because of the stiff suspension directs all the stress of the turn, into the tread, and the sidewalls don't seem to be very stiff either. I feel the car shifting on the tires, as i'm driving on the interstate, at the normal highway speeds. I didn't do any research on the tires. I just needed some tires that probably wouldn't rub. I had 215/45/17 Khumos 712's.....the insides were rubbing the spring perch, apparently. I guess i'll just have to wear the tread down real fast, Like AutoXing on them, that made my stock Firehawks stiffer. I bought two new Firehawks and Discount tire put them on the back for the snow season, and during a dry week, the back end of hte car would sway a lot during highway speeds, just a twitch of the steering wheel, the back would sway really bad, to the point that i would think it's dangerous for me. I put the new ones on teh front and the older ones, with about 36K miles on them, on the back. No more swaying after that. So the thick/tall tread must be one of the main factors that's causing this swaying motion. i thought the 40 series tire would help the stiffness of the tire as a whole, but not really. What do you guys think? and the tire pressure max is 50, and i have the rears at 49 or less.....i was thinking that would make the tires stiffer, but it didn't work....still swaying.... any tips?