Grimmspeed 3-in Catted Downpipe Subaru WRX / STI 2002-2007 / Forester XT 2004-2008

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A downpipe is one of the first modifications that should be done on your WRX and STI, as the OEM downpipe contains two very restrictive catalytic converters, killing the power potential of your car. Within our complete lineup of downpipes, you have the option to add a high-flow, 300 cell catalytic converter, fully machined and contoured flanges with beautiful brushed tubes and black ceramic coating. Whether you're racing time attack or to work and back, we've got the perfect downpipe for you.


  • Proudly made in the USA - Design, Materials and Fabrication
  • Innovative 3-D Contour Flange (Limited models only)
  • FARO™ Arm Designed - We are at the leading edge of new product design hardware
  • Flanges Fully CNC Machined (Limited models only)
  • O2 Bungs for factory sensor and aftermarket wideband AFR
  • Divorced Wastegate for Optimal flow
  • High-flow, 300 cell, metallic substrate catalytic converter
  • GrimmSpeed Gaskets Included - A $40 Value! 

For those looking to take the finest downpipe one step further and wring out every last ounce of performance, we offer our 'Limited' line of downpipes. Limited downpipes use flanges made of the very same 1/2" 304L Stainless material, but are fully machined with recesses for each tube as well as a beautiful 3D contour to smoothly transition the irregular shape of your internal wastegate outlet into our divorced tube for tighter boost control. In addition to the machined flanges, limited downpipe tubing material has a brushed finish, for a more uniform, refined appearance.

NOTE: Once you have added our downpipe to your vehicle, you must be tuned. Replacing your factory catalytic converter sometimes causes a ‘cat converter efficiency’ check engine light. You can either use tuning to delete this CEL or you can use a mechanical fix. GrimmSpeed aftermarket downpipes modify OEM emissions control devices and are intended only for off-road racing applications.


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