8.8 swap

Love this thread slot of good info. Found an 8.8 from a 2000 mustang GT. from the pictures both sides seem to be the same length and owner said it measures 60" across. I'm a missing something as to why people are cutting the exploder rear vs just getting the mustang? Also if I do this mod will I be able to find steel wheels that will fit my dog dish caps pretty easy. The whole tire rim size back space thing is not something I'm super in tune with. Thanks