Hi, the original cat is angled and awkward to replace. If I get a down pipe, then get a cat added to the b-pipe before the resonator? Is this possible/a good idea? this is for emission laws. There is going to be a wearpon r manifold and header added, 2inch b pipe all the way down to a magnaflow straight through muffler.

 

That MAY work. The O2 sensors are very sensitive to position and you may throw a MIL if you vary the location too much. Or even get one just from the new cat flowing better. But most of them can be soulved by using extenders on the Sensor to move it further out so it "sees" less flow again.

 

I actually am fabing an exhaust nearly 100% identical to what you describe. I will be using the Weapon R Race header and connecting it with a Megan 2.25" B pipe, and inserting a Vibrant HiFlow Metal Core CAT about right here:


I have to base it on rules for my SCCA Racing though. I intend to use a "mini cat" for my O2 sensor: O2 Simulator Mini Cat Cel Fix best oxygen sensor simulator made.

If it has to pass local emissions, MAKE SURE you can before you start spending ANY money. Some places (like the great state of California here in the USA)DO NOT ALLOW ANY CHANGES to the factory cat and emission systems other than pre state approved or Original Equipment Manufacturer replacement parts.