Is250C Rwd Can I Use Same Size Wheels

[djrocketodd1]

Hey all, I got this car and want to put winter wheels on it, its a RWD only, right now it has 225/40r18 on front and 255/40r18 on rear, can i put 225/45/17 lexus rims and winter tires on it? or will the different tire diameter throw a code or mess with the traction control? and will those rims fit over the brake calipers? the guys at tire rack thought changing the diameters might affect the traction control because the rears are largr diameter then the fronts right now.

Hopefully this is a straightforward question, I just dont know too much about these cars and rims.

Cheers all. hope to learn lots here!!