Are you going to run coil overs up front? Typically coil overs stick out more forcing you to run a wheel spacer to avoid rubbing or a narrower wheel and tire combo. Some people run a shorter spring to avoid contact but shorter springs (8") have higher spring rates which can reduce ride quality but is good for corner carving. I'm still not sure what your purpose is for the car.
I have 18"x8" up front with MM coil overs with 10" springs and a 235 wide tire. I haven't had the car aligned yet but I think I have half an inch clearance. I might be able to run a 245 tire. I have the BFG Gforce tires which run wider than others. My 245's have about a 10" wide tread width