the overall height of the car/tire will not be changed by using an 18 inch rim vs 17 if you buy the correct size tire. The tire will be .5 inches shorter sidewall (top/bottom) to make up the difference so you wont notice any difference there.
visually the sidewall being smaller in the back vs front would throw me off, it should be the opposite if anything lol
__________________ 2003 Cobra Vert (Redfire) #3938 of 5082 @ 05/27/2003
472rwhp/493rwtq -Modification List - Dyno Sheet 2012 Mustang 3.7L M6 (Kona Blue) 2011 Ford Edge Sport (Red Metallic)