RE the spoiler, I've got one of those, was a different seller but I imagine they come from the same factory. I was a bit apprehensive at first with the fitting as its from China, but once it arrive the fitting was pretty much spot on thankfully!
They come with a tiny roll of double sided tape, I would recommend buying more as they don't supply enough. There is small also a gap between the spoiler and roof, I ran a line of silicone adhesive around the front edge to seal it together and smooth the gap (also stops water getting underneath it):
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