Lower Ride Height Resulting from Different Wheel/Tire Combo?

Originally Posted by preR35

Hello folks, I have an '09 Sport on stock wheels/tires, Eibach springs, and wheel spacers (15mm and 20mm I believe). I've been looking into going to an 18 inch wheel and beefier tires.

OEM:
Front 245/40/19
Rear 275/35/19

Planned:
18x9.5 et12 (front) 18x10.5 et15 (rear)
245/45/18 (front) 275/40/18 (rear)

I've used the following calculator, Tire Height Calculator - Wallace Racing and found that the overall tire widths and heights in the end will be nearly identical for each setup.

So my question is, am I correct in thinking that my car would be lowered by half an inch after I make the switch, since the tire heights will be the same on either setup and I'm stepping down from 19 to 18 inch wheels?

Also, can you think of any issues like rubbing or clearing Sport brakes that I have not realized?

Thanks for your time!

- Kevin