Nothing helpful to add here. Just got my CX5 Saturday. traded from a 2012 3/4 ton Ram. That was a trade from a lifted 2004 F150 w/35" tires, full grill guard, and desert pinstripes. I couldn't imagine taking the CX5 anywhere that a grill guard would remotely be useful, much less necessary. It's a car for Christ's sake...not my beat-ass F150. Haha.
But srsly, what do you plan to encounter where the added weight would justify a full grill guard? Them things are heavy.