You could run into some understeer issues with that large a stagger (difference in width, front vs rear). I'd stick with 265/35-18 rears along with the 215/40-17 fronts.So after weeks and weeks of searching, the only rims in 17/18 that I really love are the Wedssports SA60M.
The only sizes I could do would be
17x7.5+48
18x10+36
I know I'd have to run a 15mm or 20mm spacer up front. Other than that, do you foresee any other issues. If I did these rims, I could run the new ADVAN Neova AD08 R tires I love in
Fronts - 215/40/70
Rears - 285/30/18 or 295/30/18