I've been wanting to put one on my 400EX for a while. My friend had one on his KFX700, it was pretty sweet. If you do get one, I would suggest getting a dashboard for it, too. You can mount it without one, but it's looks a lot better and is protected with the dashboards.
I'm using the 1 1/8" dashboard for my Flexx bars. Problem I had with it was fit/finish for the plastic mount adapter. I ended up having to take off the metal wire clamps that are on the stock piece. I didn't realize this until afterwards, but there are instructions on the TrailTech website that tell you to do that as well. After that, the plastic adapter fit fine. It works well, and still looks nice. I only wish there was a way to utilize the stock adapter because the stock plastic (where the indicator lights are mounted) looks nicer than the Trail Tech plastic.
As far as the Vapor itself, I haven't installed it all the way yet. The magnetic bolt for the speedometer is too high up on the caliper to be read correctly if you install it the way Trail Tech tells you to. Another guy on the forum here said he just had to pick a different spot on the hub to drill and it works fine.
My buddy has a 450R has has the Vapor as well, and he is very pleased with it. It's nice to have a speedometer, tach, and he gets a lot of use out of the temperature gauge as well.
Nash, so far the dashboard has proven to be a good clamp for my bars. I would definitely recommend getting the dash if you end up getting the Vapor. It's just more secure. Otherwise you end up trying to use this little plastic clamp to attach the Vapor to your handlebars, and it's just not that secure.
If you don't end up getting the Vapor, and you are still looking for handlebar clamps then TT sells it without the housing for the Vapor as well. But at that point you have a lot more options for handlebar clamps - might be able to find some that are just as good but less expensive.
hey nash i have that on mine and its great, it even took a 45mph roll over in dixon this week and protected the vapor, can say too much about my left front wheel and rear right wheel bent both and front tie rod, whoooo hooo sick crash , but walked away ....