It looks very nice and is a good demonstration of what possible but there underlying resolution of the car is quite low and so the reflection of the ceiling lights aren't smooth. With a highly reflective rendering like this you do really need a large number of triangles and I'm not sure that WebGL in the current browsers can support that well. Would love to see it get even better!
Number of triangles isn't going to factor much into webgl performance; because you're just batching static geometry, so your only performance bottleneck is really the hardware. Where the limitations of the browser are going to come in are on things that spike CPU work or can't be batched easily. (Simulations and more dynamic scenes)
I have recently been prototyping a WebGL based CAD viewer at work, and I could render 4-5 million triangles (that's around 50 MB of geometry data) on a late-2010 MacBook Air 11". Performance is very good on all browsers (FF, Chrome, and Safari), but FF seems to outperform the rest.
I would love to see a webGL CAD viewer, as a product designer I spend most of my day with Solidworks open and have often thought a tool to convert iges/step files into a format for webGL would be really good!
Coming soon! I am just getting the payment system in place and some legal issues need sorting out. The website is Babel3D - http://www.babel3d.com. Right now it only converts for visualization on mobile apps though.
Having said that, its a good job!