Ok I have a BSP XB and I have it lowered on Tanabe DF210's. I just recently got 18" 5Zigen Hyper 5ZR's and Hankook tires. I've been having a problem with the car feeling "out of control" or like it's flying when I hit high speeds. There's also a little vibration in the steering wheel and it's totally different than the way the stock felt. I already got an alignment and that changed it a little, but it still seems like somethings wrong... anybody know what this might be??

 

tire pressure?
wheels balanced?
tires the same size?

 

Are the wheels hub centric? If not, do they use centering rings? If so were the rings installed?

 

they have no centering rings so im gonna try that but where do you get those from?