20Gs are slightly larger than the GT28RS. I would say 18Gs are closer to GT28RS though. One of my neighbors from years ago used 18Gs on his Z32 and that thing was a monster for the time. He let people look under the hood, but you really couldn't see much. Plus, he was pretty tight lipped on what all he did or had done to the car.
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 2007 350Z NISMO #0618: Zerolift | UPREV | F.I. | Greddy | Competition Clutch | Injector Dynamics | Aeromotive | Pioneer | JL
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