I guess this is what the GNX rear setup looks like. No mistaking this setup. However, I think someone makes an aftermarket assembly.
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Yeah Kirban makes a replica of the GNX rear suspension... I think it costs about 5 grand and they will install it for about another 2 grand. It's a big job but I hear if you have the money it's offers a huge handling and traction enhancement. I'm pretty sure that one in the picture may be a replica.