Not too bad really.
The Speedymoto bars I use are a little on the short side anyway - but I usually pull the bars back a little to match the natural angle of my grip. With the CRG mirrors it is more narrow than the napoleon bar end mirrors.
If you want it more narrow, you can cut most bars and/or remove the pins on the controls to slide them up. This would give you more room for the mirrors too.
On my 06 SC, we used a bar end mirror adapter that added about 1/2 to each bar. You can mount the mirrors directly to the bar and narrow it another 1/2 inch.
I worry more about the bags on my ST because I can't see them. I have bar ends on that bike and I don't have any problem splitting lanes--even in town.
The highly visible bar end turn signal is worth it to me in traffic.