Not trying to be a d!ck......but if you go under the car often enough to try random fixes, why not just adjust the height of the exhaust? If the exhaust is making contact with the x-member, I would try to re-align the exhaust before I go jacking around with the x-member.
Good luck!
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 2007 350Z NISMO #0618: Zerolift | UPREV | F.I. | Greddy | Competition Clutch | Injector Dynamics | Aeromotive | Pioneer | JL
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