Spoke with Mike yesterday (xstric9x) who followed me and said my nismo zorst sounded awsome as he followed me up the Horshoe pass, one thing we have both noted and certainly in my case if you take the zed out on a good run the nismo seems a lot louder at the end of the day than at the beginning
He also says the same with his zorst, that when fully hot it sounds much louder.