Which should I start with?

christian370z

It goes: headers --> mid-pipes --> Y pipe --> muffler. Four sections in total but the most restrictive are the OEM cats and Y pipe in my opinion while the best of those two in terms of bang for the buck is definately the HFC.

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-320whp / 259wftlbs-
SP Rays -- RE-11s -- SpecialtyZ Tune -- Swift Springs -- Stillen 25R Oil Cooler -- Stillen G3 Intakes -- Berk HFCs -- F.I. 12" CBE -- Stillen Sway Bars -- Es14 Spring -- INGS+1 lip -- CF Spoiler -- GTR Start Button -- VLED Parking Lights -- PWJDM V2 shift knob