Well those wheels are really sunken in, basically like your stock setup and front is 5mm more retracted compared to stock. I would skip those and go with the basic vendor recommended setup. No modifications or anything else needed with these.
18x8.5 et35 235/40/18 or 225/40/18 front.
18x9.5 et35 265/35/18 or 255/35/18 rear.
Would look like this
http://www.turnermotorsport.com/imag...left_front.jpg
http://www.turnermotorsport.com/imag..._left_rear.jpg
http://www.turnermotorsport.com/imag...-left-rear.jpg
http://www.turnermotorsport.com/imag...black-side.jpg
http://www.turnermotorsport.com/imag...left-front.jpg
http://www.e90post.com/forums/showpo...97&postcount=8
If you really want to go with the specs you said then rear tyre either 255/35/18 or 265/35/18. You don't need to go with 245 wide and 255/30 is wrong aspect ratio.