[1slow96]

Mine were widened to 10" ,but 10.5" would have fit with 315/35 Mickey Thompsons.
Replacing wheel studs with longer versions from ARP will give you the freedom to add
spacers to one ,or both sides for aesthetics ,etc. I have used up to a 3/4" spacer on driver's
side. With a 5/8" on passenger side as the housing end is about 3/16" further out on this side.

 

[1slow96]

The drivetrain is not perfectly centered to begin with. Design requires more room on driver's side
for steering ,brakes ,etc. Not sure if opposite is true on cars made right hand drive. Handling seems
improved as rear track widens. Front end geometry ,alignment ,scrub radius ,etc. can make a huge
difference. Any diagrams that include rear do so with intersection points ,angle(s) to an imaginary
straight line representing rear end housing. Hard to see how moving either/both rear tires outward
could introduce negative handling characteristics. Nor have I been able to find any published research
that indicates this.

 

[1slow96]

An example of a 3/4" spacer. Though shown on left front in this photo.

 

[1slow96]

Thicker spacers allow tighter turns w/o hitting sway bar. Currently have a 5/8" spacer on driver's side. With 5/16" on passenger side. Tire/wheels are equal distant in relationship to wheelhouse. Wider wheelbase seem to offer more stability, but have not studied those effects nearly as thoroughly as the measurements themselves.