The stock O2 sensor housing that came with your DSM is a cast iron piece of crap that sits between the turbocharger and the downpipe. In addition to its role as a holder for the oxygen sensor, the O2 sensor housing joins exhaust from the wastegate port with the exhaust from the turbine outlet and this joining can cause boost creep and excessive back pressure. Replacing this piece with our more free-flowing unit can yield benefit in horsepower as well as the prevention of "boost creep" . This is a direct bolt on replacement of your stock O2 housing. Mandrel bent 2.5" tubular o2 housing with atmosphere dump. Built with mild steel,  O2 bung and laser cut flanges. We also offer:  External waste gate flange instead of the dump. "must specify type of gate to be used." T3/T4 style O2 housing Dump Style. (may have to adjust your downpipe) T3/T4 style O2 housing with external Waste Gate on housing or off housing for those who have it on the manifold. $120.00 +$20.00 S/H  "contact us for pricing on any options"