Will 10 inch wide wheels fit my Demon?

I run a 10" wide rim with 28X12.50 MT ET tires on my Demon pretty tight fit. I have 5" backspace and have the 3/4" spring relocate on each side with stock wheel wells.

I believe you could run a stock (unmodified) setup with a 10" wide wheel and about a 4-3/4" to maybe 4-1/2" backspace might have some rubbing depending on your tire choice and car height. Me personally I would look for about a 4-3/4" backspace and you could always use a spacer to move tire away from spring if you have to.