I have never had an issue buying Grey from reputable Grey outlets here in Oz. D3S D4s D5 200-F4 and the list goes on.
Service, supply, has been excellent. A two week turn around to Hong Kong - Japan for any repairs - service.
New items once paid for are delivered from Hong Kong or Japan usually in 4 days door to door inclusive of weekends.
ie: pay on a Thursday night, receive it on Monday pm or earlier in nearly all cases.
My Grey products (OUT OF WARRANTY) in the past have always been accepted for service by Nikon, that said warranty logically needs to go to the supplier.
There are risky suppliers, granted, there are scams, that's the world we live in, sadly.
Only an opinion