Hi mike. Yes of course you need wider wheel. Dont fit 265 on the 8.5" fronts.
I think 9" will work however. But that is a different topic altogether.
Back to the topic. Spacers increase track width so make the car more stable and as othere said it can help to dial out
some understeer. However the root of that evil lies in the staggered tire setup.
With that said i probably would go for 12mm all around.