In our testing, this is what we've found using the 18x8.5" ET45 on the front of the F22:
18x8.5" ET45
225/40-18 tires: 3mm or 5mm spacers required, no camber adjustment needed
235/40-18 tires: 5mm spacers required, no camber adjustment needed
245/35-18 tires: 5mm spacers required, -1.5º or more of front negative camber
255/35-18 tires: at least 7mm spacers required, -2º or more of front negative camber
The rear is much simpler with the
18x9.5" ET58: 255/35-18 is a direct fit and 265/35-18 may require slight trimming of the shock dust boot or inner fender liner to prevent rubbing. Alternatively, 5mm rear spacers can be used to eliminate rubbing on the inside.
Here's some photos of a 245/35 front with 5mm spacers and 255/35 rear setup with EC-7 wheels in the same sizes as your ARC-8s:
--Dylan