I would be happy to install 4.8is exhaust to my 4.6is. I think it sounds just right, a bit throatier than 4.6
I've heard Eisemann Race exhaust video and I think that's too raspy.
But, if Dinan exhaust sounds same in 4.8is as it does in 645 then that's just great, my neighbour had one and it was music to your ears