Hi, I just did the switch that you are about to do with black wheel, amazing difference in terms of look and such a new handeling with larger wheel & great UHP tire!
I choose DaiAlloy Staggered Autobhan black wheel.
http://www.daialloys.com/wheel.php
I went 18x9,5 in front 35mm offset with a centric 16mm spacer (if you want to go 9.5 width in front you need at least a 15mm spacer, otherwise the wheel touch the connecting bar at the top and you need to cut the extra length of the top bolt on this rod to avoid dammage on the tire). You also need longer screw for the wheel, length is not an issue because you don't touch anything inside the disc. I needed 12x1.50 17mm shank by 40mm long to match my mag and it worked.
For front tire I went 255/35R18 Conti SportContact 5P. That is the biggest you can go. Next one I will go 255/30R18.
For the rear I went 19x9.5 25mm offset witn a centric 10mm spacer (10 inches width would work). The spacer was not mandatory but since I was larger in front, I wanted to balance the car.
Rear tire are 295/30R19 Conti SportContact 5P. You can go bigger if you want, but for me it is way enough.
IMPORTANT: For the wheel bolt, I had to cut 7mm of it in order to avoid dammaging the macanisim inside of the rear security brake drum. Make your test by spining the wheel to avoid problem.
Here are some pics of the project. You can see difference between OEM wheel and 225/40R18 front tire & OEM wheel 275/30R19 rear tire, and final result.
I really like the final result, look like I have a new car
For full details I have a thread named :
NEW TIRE COMPATIBILITY: 295/30RZ19 rear & 255/35RZ18 front = SUCCESS!