Correct Offset

[Papercup]

Mine have 38 offset front and rear. front 17x8 rear 17x9 no problems with fit or rubbing antwhere,

same here, 17x8 and 17x90, 40 offset, tight at the back but no rubbing even on track in a hurry
 
arches are not rolled
 

 
this is very useful
 
http://www.driftworks.com/resources/wheel-offset-calculator,17.html

[Kevin]

I run 18 x 8.5 Front + 30 and 18 X 9.5 Rear +30 and have no problems at all.