The problem is that we're talking about NOMINAL #'s...
One tire with a 225 width isn't going to be the same as another's 225 width.
I've had a pic of my 8.0", +30 fitment with a 215 wide tire up front with stockish (unknown brand spring on GAB shocks - think KYB AGX) front suspension, and I manage to stuff a 6mm (~1/4") spacer in between the tire and the (bottom of) the spring.
If we do the math, a 225 wide tire would basically eat up all the space...
Yes, I've heard of 8.0", +35 spec wheels fitting up front, but I wouldn't risk it from my experience; be prepared to run a thin spacer just in case you hit stuff up front...
Watch out for aftermarket springs, as I know for sure the Tanabe GF210 and Tein's run larger diameters on the bottom coils, which gives you LESS clearance on wheels.
I'd put money these spring + a 8.0", +35 wheel will almost never fit...
Aftermarket coilovers might be a problem, as most will run a 7" height spring up front.
This means for most people that the adjustable lower spring collar will most likely be adjusted all the way DOWN.
Again, this DECREASES clearance...
Realistically, you can run 225's for square fitment.
If you get the (front) offset spot on, you can run 235's.
I find that FC's running close to 300 (or more) can easily overpower these narrow tires with the right foot.
I really like running 255 square, but it's next to impossible with stock front fenders...
I like running 255 / 40 / 17 tires on 9.0" wide wheels; you need an offset of around +20 (minimum) to +15 to get them to clear everything up front.
The problem with this combo is that it'll hit the fender lip!
Wider (fiberglass) fenders are an option (which I don't like) or serious modification of the stock fenders is needed.
This 255 square set-up is fun with FC's running in the 300 - 400hp range, which covers most of the cars out there that are modified.
I have fitment pages for wheels and tires here:
http://fc3spro.com/TECH/MODS/RT/rims.htm
http://fc3spro.com/TECH/MODS/RT/tires.htm
-Ted