I am pretty sure that this was covered a bit a while back, but it looks like they are progressing a bit, and from what the captions say - are actually tuning these things to make power... Curious about these - they are extremely sonorous; really brings out a great noise from the S65 :-)
http://www.youtube.com/watch?v=jpeqshEC2PI
Almost too much noise - but with the hood closed, I am sure it wouldn't be too bad... Still don't like the fact that the engine would be breathing in dust.
Cheers.