i recently purchased a set of monster motor works headers with the s-pipe and i was wondering that i might need to take off the catalytic converter to put on the headers and my injen cat axlwe back exhaust

wow, sp? between the header and axle back, you should be able to keep one of the cats.

appreciate it i am new in the scion game and i was told the weapon r headers required you to take off the catalytic converter and the mmw headers and those seemed to be made the same .

^^ I'm pretty sure they're the same exact thing. MMW= Weapon R

There are two cats in a tC. One is in your exhaust manifold which you replaced by switching to a MMW Header. The other is right after your S-Pipe, the begginign of your mid-pipe, which is still stock since the injen exhaust is only an axel-back.

i thought injen was cat-back? then you will have no cats at all

Technically, a cat-bat is an exhaust which starts at your cat and replaces everything behind it (hence cat-back) and retains your cat. Our exhaust consists of 4 pieces; exhaust manifold(which has a built in cat, and is eliminated with an aftermarket header), the s-pipe(down-pipe), the mid-pipe(which houses the other cat, it's right after the s-pipe, beginning of mid-pipe, and then finally comes the axle-back which contains the muffler. The Injen is an axle-back since it is only the last portion of the exhaust and connects to your mid-pipe, however Injen markets it as a cat-back since it doesn't eliminate your cat, yet when most people say cat back they mean s-pipe-back, though the 2nd cat has been eliminated. I hope that helped, it's kind of confusing, now that i read it. Headers+1stCat--->S-pipe--->Mid-Pipe+2ndCat--->Axel-Back

^^ i know that information, but i didnt know whether or not injen was cat-bat, thanks

just like they advertise dc headers as 4-2-1 but its not

DC is weird, it's in between. Though the 4 pipes merge into one, it's split inside by a divider until it joins the s-pipe.

^^ i know that information, but i didnt know whether or not injen was cat-bat, thanks

just like they advertise dc headers as 4-2-1 but its not

DC's header is 4-2-1...just a odd 4-2-1 design

^^ that means not TRUE 4-2-1

only true 4-2-1 headers are MMW & the new Tseudo