BTW after more research I've determined the proper torque values per Nissan as 39 ft lbs at the CAT connection and 43 ft lbs for the resonator and muffler connection. I wanted to correct my previous recommendations based on bolt sizes for the record. See attached pdf.
Of course the torque values Nissan provides are for Nissan's components, not HKS components. Since HKS designs and manufactures the components and sources the bolts/nuts it's their responsibility to provide the proper torque values for their product, not tell customers to go find Nissan's values for Nissan components and use the same.
untitled - EX.pdf.pdf