i got my mazda 3 feb of 2006 and installed a set of staggered size 18 rims. it looked really cool on a set of 225x45x18's. it was already rubbing on uneven surface at the stock height. i couldnt even take 2 skinny passengers with me to sit on the rear. the look improved but i wasnt satisfied so i had H&R sport springs installed which dropped the car about 1 1/2 inches in front, and 1 1/3 behind. man, i always got a 2nd and 3rd look whenever i'm cruising. but the downside was you could not go full speed without worrying about any potholes or uneven roads ahead of you.
recently, i just got crazy and sold the 18's and switched to 19's. this time, i installed same sized rims front and back hoping to cure the rubbing factor. it was too late when i learned that the offset played an important role to avoid the fender lip kissing the tires. i thought i solved my problem... but obviously i didnt. the car looks meaner and you get people staring at it now because very few japanese cars are mounted on 19 inch rims. still cant run it full speed. i was told that my last recourse is to have the rear fender lip folded or rolled upward. hopefully, that extra half inch out of the way will cure the problem. if anyone has another suggestion, please post it.
just make sure your specs are accurate before you install your 18's so you could avoid the same problem i did. good luck chief!!!