The Z34 plenum looks like the same ones that come with '07+ 350Z HR motors. I don't recall hearing anyone complaining about cracking the stock plenum. Who knows what forced induction would do to it in the long run.
The Takeda spacers are different. It's not the "gasket" that surrounds the plenum, but it's the area with the 6 hole cutout into the engine. O_o I'm not sure how it all fits, but definitely curious.
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