Fox rear wheels 9" or 10"?

[m_owing]

Thinking of getting new wheels for my 88 mustang. 4 bolt from lmr or AM. Currently I have a 17x9 with 275 tire lowered on Eibach pro kit. +18mm offset with 5.75" backspacing. I've rolled the fenders and flipped the quad shock.

So a 17x10 (+20mm, 6.29" backspacing) might fit, might rub on the quad shock or the fender?

Is the only advantage of a 10" wheel to run a wider tire and line up with the body? Is there anything else to consider?