the wheels are a 40mm offset, 7inches wide 5.5\" back spacing and 1.5\" front spacing.
i have the 3\" narrowed beam, 2.5\" dropped spindles, and went the extra mile the airspeed 3\" narrowed sway bar.
i have been told the discs might push out the wheels a bit, but nothing substantial
i am running 205-40-17's with a total height on 23\". you would be able to run 18's with low pros no problem i think, the only thing is you might not be able to go as low as me. that would be my only thought.