I need tire size suggestions

I recently bought a set of 355 wheels for my 87 3.2 Mondial Cab, and I need to decide on an "appropriate" tire size to go on these wheels. I'm presently struggling with the dilemma of keeping the stock height (will retain the same performance level, but will leave more fenderwell room than I like) or go with a slightly taller tire (use up some fenderwell space, thus looking better, but will lose performance from a car with already less power than I wish it had)

The replacement tire sizes I've come up with - ones that will keep the same ride height - are 225/40-18 front and 255/35-18 rear. These sizes deviate from / are taller than stock by .2" and .1" respectively (though probably imperceptible, the front tire will be very slightly taller than the front, thereby getting rid of some front rake that I really don't like - I prefer for a car to sit completely level)

Am I on the right track with all of this? Any of you with 355 (or other 18") wheels have any suggestions or comments?

 

Any clearance problems / issues? Is your car lowered? (in my opinion, the amount of fenderwell "fill" on your car looks perfect!)