Most that upgrade to 10.5' wheels in the back run about a 20 offset. The 19" forged wheels are 8.5" w/33 offset. Add a 25mm spacer and now you are @ 8 offset. On a 8.5" wheel that would be almost ideal.
current wheels specs:width: 8.5" offset: 33new specs with 25mm spacer:width: 8.5" offset: 8
Inner clearance 25mm more(inside of wheel to strut housing)
outter position extends 25mm (position of outside edge of wheel)
current wheel specs:width: 8.5" offset: 33
New wheel specs:width: 10.5" offset: 20
inner clearance 12mm lessouter position extends 38mm
Up front I would run a 20mm spacer.
I would also run longer wheel studs as well. 25mm = 1".
http://www.1010tires.com/WheelOffsetCalculator.asp