You gotta love planning mods for a car you don't have yet

What offsets and widths on Fikse rims in 18 or 19 inch will work for an S2k lowered with springs of some sort (KG/mm race for example)? Looking for as much width as possible front and rear, since I'm considering going SC. Are 19's and lowering too much to ask? I don't want the rims to stick out and I don't want weird wheel gap... what are the options? I've seen that you can run 285/30-18's in back. What about in 19"? What is the widest you can run up front?

Thanks in advance guys