I say pull an AceInHole... beat the living hell out of your fenders, run 18x10s, and throw on some 285/30/18s.
Dreaming aside, you would probably be fine with 235/255. But you could also consider 255/35/18 up front and 265/35/18 or 275/35/18 rear since those will be just as short or shorter than 235/40 and 255/35. Just have to work the fenders and get proper backspacing. veilside180sx's custom Konis give lots of clearance if you're thinking about changing suspension.