laser rear fog light

I saw this conceptual idea on Audi's future Q7, and really liked the idea.. ( http://blogs.artvoice.com/avdaily/2012/06/05/rear-fog-laser/ )

So I guess my question is that although I'm considering doing this, what size laser should I get that would be bright enough? I already purchased a red 5mW line laser module, and it wasn't bright enough, and I was thinking about using a 30mW or 50..

Please don't try to tell me why this looks like a bad idea, I know the dangers, and it will only be used when absolutely necessary, but what do you all suggest?

It is difficult to know if it will be bright enough as it depends upon your set up -if you will be using the lasor to project on to a transparent screen to achieve the fog light effect, or firing directly to the environment, etc etc etc.. Cool idea using lasors, BUT, from the little I know of them I hear that they become dangerous to vision at 5mW in power. & they are prone to overheating. I sidestepped all the lasor issues and have neon tailights now, with the standard bulbs in position as a backup. :)