I run long tube headers that come together at a 3" collector. That goes through a 3" ID x 6" OD x 18" long resonator and dumps straight down behind the Cabin and I was on the SCCA limit at Nat'ls. The car is PLENTY loud made tolerable by the purr that Nissan's are known for. When I'm on the pipe, it's music.
Please run through at least one big straight-through resonator or two small ones and point all that to earth!!!! Besides you don't want to give up too much low-end torque with an open system.
Guys like me (and plenty of others here), who play by the rules, don't want the limits dropped because of those who make too much racket... 
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2011 Nismo with...Stillen Gen3 CAI, FI LTH's, Stillen CBE with Springfielddyno rear section. Stillen under drive crank pulley, UpRev, and LW flywheel. Penske 8300DA Valved by ANZE, SPR FCA's, Stillen F/R adj. sway bars, Enkei PF01's, and Hoosier A6's
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