View Single Post
      06-16-2011, 07:30 PM   #2
kitw
Colonel
kitw's Avatar
471
Rep
2,991
Posts

Drives: F91 M8, 991.2 GT3
Join Date: Jun 2007
Location: Bay Area, CA

iTrader: (20)

The challenge street will pass the tail pipe and OBD-2 tests, but won't pass visual since it eliminates the secondary cats. (most places won't catch this)

None of them will produce power without removing the primary cats, though. You might as well do a Challenge Sport, Turner test pipes or Innotech if you don't mind some rasp. The Gintani/MXP/Fabspeed that put HFCs in the same position as the stock cats won't make power like the the ones that move the cats downstream.
__________________

DSC_3369 by Kit W, on Flickr
Appreciate 1