My subcompact XD (I don't have a 4 or 5" XD), as measured by my caliper (not a digital to .001, but an okay old mechanical)
Slide width at widest point = 1.090"
Plastic frame width just below slide = 1.190"
grip just above magazine = 1.210"
Widest part of grip (includes the raised thumb "lump" area) = 1.264
Absolute widest point (includes protrusion from slide release) = 1.286"
If comparing to other guns, bear in mind Springfield measures the overall length the way I would (total length from end of barrel to whatever point extends farthest back, be it beavertail, slide, etc.). Some (Glock) measure the total slide length, but neglect to include the portion of the grip that extends even more behind that point.
Hope that helps.