Unfortunately in our D16Y7 cars, you WILL lose the catalytic if you replace the stock headers with aftermarket ones. Big drawback too, because it'll require you to relocate the 2nd (bottom) 02 sensor, by legnthening the wire to it, which will cause increased resistance to the sensor, causing it to read incorrectly. Point being, that method can't be done, you'll have to get an
02 dummy sensor to put in it's place. Good luck with it, if you decide to go for it, though.
