Hi can anyone help me out I have a xf ford Fairmont

I want to fit street pro II convo all around..
What specs do I need. With shock diff/guards etc:

I was thinking
For rears 15x8.5 backspace 3.50
Fronts 15x7 backspace 3.50 Will these fit comfortable


I here some people runs 15x8.5 backspace 5.00 for rears