18x8.5 Wheel offset?

[2014 Blue RS]

Not sure what they cost or weigh but, says they can be ordered in 5x105 with any offset. Don't know anything about going flush. I just really like the look of an extra wide wheel. Any thoughts on the best offset? Still just looking/learning.
Niche Wheels

 

[Black Turbo LTZ]

30-35 ET with an 8.5" wheel will look perfect. I ran 17x8.5 with 34-35ET and 5mm spacers and I was flush

 

[2014 Blue RS]

Thanks Black Turbo LTZ
Will i need spacers too? I've found a few wheel sites that will do custom 5x105 and off sets.

 

[MidnightClub3]

Bump for the same issue, anyone?. (offset for 8.5 wheels to clear stock front suspension)

 

[gringoo27]

fronts are 18x8.5 +56 (25mm adapter) total offset +31