Installed the Car Chemistry inserts, three disc, directly into the end of the header pipe just prior to the inlet of the muffler. Along with a custom made muffler from Arizona Exhaust ( now retired ? ), resulted in a quiet system.
Unknown has to how much back pressure, if any, the discs created, but not noticeable in normal street driving.
Did not install either the restictor which narrows the center tube in the discs or the cap on the center tube which forces all the exhaust gasses into the discs
Reference the Summit Racing site for Car Chemistry:
http://store.summitracing.com/produc...earchType=ECat