well i just found out that i forgot to install the rubber rings along with my rims. my question is, will this damage either the rim or the car?

 

if you mean the hub centric ring then yes you need to install them.. unless you enjoy the shaky ride at 80mph

 

I'm such a freak with my tires being balanced.
I've had the wheels off my car a 1/2 dozen times already and this is the first I'm hearing of this.
I'm sure that this is the problem. Where can I get a set for my IS250?