Thank you C-Note. very helpful information about the differences. So will I still have problem with the 02 sensors? I have the two small cats left and the two RT High flow cats.
Looks like everyone touched on the questions about the O2 sensors, I was talking about the wiring problems. When you put the headers on there will only be room for one cat, the collector will be where the forward factory cat was. this means that instead of the O2 sensor being just behind the first cat in the wheel well it will have to be under the side sill between the cat and muffler. This is not the greatest place for the sensor as it gets to hot under there and can take out the wiring causing the for-mentioned reverse solenoid problem and throwing an engine light. Another problem is that the wires will not reach into the side sill area and you will need extensions. Another solution is to install cat Simms, being as how the post cat sim is only used by the computer to monitor the cat and not for tuning simms will not adversely affect anything else.
I ended up faking out my computer by placing the post cat O2 sensor on the outside of the collector and wrapping it up with the heat wrap that is installed on the entire header. In a year it has thrown the engine light once telling me that the downstream (post cat) sensor did not heat up fast enough. Simple two minute fix if you have a scan tool.
Also, I strongly suggest that you put heat wrap on the drivers side as headers have been known to overheat the clutch fluid where the line will be very close to the new headers. There is also some wiring that could be damaged in the same area, and if you do the drivers side you need to do that passengers.
My car is running Bellangers, High flow cats and Corsa track exhaust. It was a little loud with the Corsa before the cats and headers but now it is crazy loud! I like it but it is a bit much for most people that hear it. I am sure that my supercharger makes it a bit louder but thought you may like the warning.
If you put your car on a dyno after you are done you may find that with the new headers you are running a little leaner than you were before. If you send that dyno with the fuel curve and your PCM to DC they can adjust it and send it back to you. As it turned out on my post header dyno run I was at acceptable levels but was a little leaner than before.
I learned all of this as I went and I wish I would have known some of this going in.
Let me know if you have any other questions.
By the way, where are you in Hawaii? I go over there all the time and have many friends on the Big Island.
