I've got one on mine...... it's awful! It was on the car when I brought it, looks like an after thought and has since fallen off! Quality! Probably more to do with how it was fitted but either way it's not brilliant. I haven't got any decent gauges on mine so I couldn't tell if it was working as it should or not.... my guess is not.
If you're looking at getting a new one then some of the other guys here will probably be able to recommend something to you
