exhaust question
The Magnaflow cats have bosses for mounting both sets of O-2 sensors. The ECU monitors cat performance by measuring what is going to the cats and how clean it is coming out. Many custom tunes will allow the rear set of sensors to be truned off, so it does not matter how well the cats work. I installed a set of the Magnaflows with a stock, unmodified ECU and had no problem, but the cats were fresh and clean. I did not run them long enough to see any long term effects.


