Yep, GD manifold will bolt onto 99/00 heads, but you'll need GD injectors and fuel rails too.
Which is a good thing as they can be made to flow 816cc with about 5 minutes work.
Also, the TB sits closer to centre of the block to the GC manifold, which means you'll need a little bit of dicking around with intercooler piping, or a longer silicone joiner. But as it looks like you're flipping it, you'll need custom piping anyway.

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Balls.