Looking at the photo, it's poking up so far in the air that stuff like downpipe clearance issues would be adjustable depending on the pipe-making skills of the downpipe maker?
I'd need a diagram to understand why you couldn't fit at least the same sized downpipe as any turbo fitted on that side of the engine ... or are you thinking the header itself could be in the way of the downpipe & that the downpipe needs to snake closer to the block than those headers will allow?
edit
OK yeah I see what you mean, seems others in wrong-hand-drive countries have run the dump OVER the header and there's potentially some clutchy & brakey stuff back there ...