Fullsize axles or heavy-duty full size axles? Look, I've had a 14bolt rear and 3/4T D44 front combo(couldn't find a D60). Excellent axles for hardcore fourwheeling.....crappy for everything else. Along with all the beef, you get alot of weight. That extra weight is a penalty when it comes to fuel economy, parts breakage elsewhere on the Jeep, and they also slow the Jeep down and take away it's "Jeep" feeling. A big old cast iron granny low four speed and some one ton axles will make it feel like you are driving a short wheelbase, convertible dump truck. If that's what you want, then more power to you......you'll have one hell of a trail rig. Just be aware of the downsides.
Street legality--- If it fits within the DOT maximum width guidelines, and you have fenders covering the tires I think it would be legal just about anywhere.