Hi
I have an MRA windshield that I have used on my Z650. On how much of a difference it makes, quite a bit in my experience. It certainly keeps most of the wind off my chest and makes longer rides at 120-130km/h much easier. The occasional spurts of +160km/h is also more enjoyable with the windshield. I removed it recently simply because I just don't like how it looks and don't ride on the freeway much. If you do a lot of freeway riding I would say get one.
I have an MRA windshield that I have used on my Z650. On how much of a difference it makes, quite a bit in my experience. It certainly keeps most of the wind off my chest and makes longer rides at 120-130km/h much easier. The occasional spurts of +160km/h is also more enjoyable with the windshield. I removed it recently simply because I just don't like how it looks and don't ride on the freeway much. If you do a lot of freeway riding I would say get one.