As the title states, I just picked up the weapon r race headers (fingers crossed :I ) and im getting a 2" pipe all the way back so going a highflow cat and res. (which will both be welded into the bpipe) ive narrowed it down to 2 of each. which do you guys recommend?

cat 1. (without 02 bung)

Magnaflow High Flow CAT 2" 200 Cell Metallic | eBay

cat 2. (with 02 bung)

High Flow Metal Race CAT Catalytic Converter FOR Exhaust 2" 200 Cell | eBay

resonator 1. round stainless steel

Muffler Resonator 2" IN OUT 15" Long Stainless Steel NEW Holden Ford Toyota | eBay

resonator 2. oval, not sure what metal but magnaflow has good rep!

Universal 16" Boomer 2" I O Glass Packed Resonator | eBay

I currently have a 2" axle back to a magnaflow oval muffler, beautiful sound, these headers are going to make it loud, but a bit more volume would be nice! should i go oval resonator to knock back more sound, or go the round?

 

and do i need an o2 bung in my cat?? considering it'll be about a foot further along the exhaust than stock

 

Put the bung in at the same length down the system from the header as the old two.

If you have the time and tools try it with the bung just tacked into the hole at the depth of the stock one (the section in the exhaust flow). Then if it throws a MIL break it out and pull it OUT a tad further and try again until the MIL goes away then finish weld it.

That is what those adapters do to get rid of MILs they move the O2 sensor farther out so they "sample" less of the exhaust flow.

 

cuel, so get the non sensor cat? the stumpy magnaflow one

 

Depends you need the sensor installed as close to stock length from the header as possible so it depends on what you have between the header and the cat.

 

Sorry the weapon r race headers come with a test pipe attached so the cat will be after the Test. (Welded to the top of the b pipe) I've been told the gd has 2 O2 sensors one pre and one post cat so have been told to get a cat with the 02 bing

 

That will probably throw MILs as it is too far away. Just measure the position of the stock one from the head where the header mounts then measure your new system and install it in the test pipe or cat depending on the measurement the same distance from the head as stock.

The first one in line is the one you want correct the second one can be moved a bit.