I'm just finishing up something similar. I chose Foose 18x9 wheels all around since that's the widest available. I ordered them through motorsport-tech.com. Then I had them widen the rears to 10 1/2". Then ship after finished. I got KORE3 Z51 brakes all around. The ZO6 brakes were just too tall and too fat for my wheels. I got the 2 piece DBA rotors that are just beeUtiful. All went together pretty smooth other than I had to get motorsport-tech.com to make me a 1/2" spacer for the driver side rear to get the tire off the frame. I'm running 335x30 rears so you got to get them centered up just right.Trouble is I'm looking at using a non-OEM rim. Perhaps I should take this offline.
They are 18x9.5 with a -4mm offset and 5.031" backspace, might even go with 18x8 with a +2 mm offset and 4.517" backspace up front though if clearance is going to be an issue with those I'll just ditch the staggered approach altogether.