Because your original post said you were thinking at a Zuma I feel I have some useful input for you. I have an 03 Zuma with light mods (Pipe, variator, etc,). I use it for offroad bashing while camping every summer. I am amazed at the Zuma's ability to smoothly travel on the road to dinner while camping. Then after dinner hit the trails and I have actually kept up with enduro bikes on the trails with a Zuma!
As for the Grom...I am planning to purchase one on arrival to the USA. I have no plans to use it offroad. I am sure a gaurd can be made but that pipe looks like a rock smashing waiting to happen. I think it will make a great hooligan on road machine. I am leaving the offroad play time to the Zuma