When I first saw the G450X in the flesh I thought it was a 125 or 250 I hadn't heard about, it looks so light, but no it says 450 on the sticker so it must be. Stock HP is 41hp but can be chipped to 52hp (no extra cost) or if it's too powerful for you, you can reduce the power to 26hp.
The one I rode was the standard 41hp. Not being a test rider or a journalist, I can't do it justice except to say it went like a rocket and put power to the ground like nothing I have ever ridden. If I had £6200.00 I'd have bought one then and there. My XR650R was a great bike but I couldn't use the power because it just spun the back wheel, the BMW just goes and wheelies like a two stroke.