Aww that sounds amazing. That has the perfect pitch the M45 deserves. It's deep and authoritative. Be careful with finding a source.
From that video link I then enjoyed this piece of greatness.
http://www.youtube.com/watch?v=rPAIcBGwqDs
http://www.youtube.com/watch?v=PMps4F_jx7oAnd this abuse to a great Anniversary edition Q.
It seems that southern Asia (It looks like a Thai license plate, but I am not sure) has been taken over by a fad that is not really big here. That looks like some serious investments in these cars.
I am very interesting in trying to help find this exhaust and I think between the many M45 members here from all over the country we can find something. I will see if I can find anything although I though I had searched through enough translated VIP magazine pages to find the most interesting options for the M I neglected the YouTube.