take a look at my car in the stance thread. The Ronal's are 15x7.5 et25 (which is about 5.25' backspace). To me, the 15's are the perfect size for this car (again, everyone has their opinion on this) These hit my coilovers (not the brakes you need to worry about as I have the big brake kit too) so I needed 15mm spacers up front, and 12mm in the rear to clear the suspension. I do have flares, so it buys me a little more room than a non-flared car.
There are several online calculators that are great to determine offset and backspacing (below are a few). That paired with a straight edge and a tape measure you will find wheels/tires that fit the first time and not have to worry about returns or re-buying different parts in different sizes. Measure twice, buy once!
Offset / backspace calculator: http://www.gtsparkplugs.com/Offset-to-Backspace.html
Tire size calculator: https://tiresize.com/calculator/