There is a rubber seal on the end of the part that sits against the turbo. This is not on the stock version.
I fitted mine and rang racingline as the stock muffler has a square moulding on the outer ring and fits facing the firewall. The racingline part is not the same and fits in any way, there appears to be no right way. You can have the motif at the side, bottom or top as all the bolt holes line up which ever way you fit it.
The guy at racingline pointed me to their youtube video but that didn't help with which way up you fit it. My motif is at the top but maybe I should rotate it so it's at the bottom???
The rubber seal makes the unit sit proud by around 2-3mm and tightening the fixings draws the part in and forces the seal tight against the turbo.
You can also see one of the bolt holes on the stock version is squared off but not not the racingline version. All a bit confusing !!!