High Flow Cat Question

Hey i bought a Header and Cat, the output plate on the cat is trianlge shaped and has 3 holes... my exhaust plates are oval shaped and have the 2 holes. What does that triangle 3 holed Cat plate connect onto? is there a plate convertor or something? Here is a pic to help.
http://www.js-autoonline.com/pics/SGI/Header_Cat_Civic8800.jpg

it connects to ur cat back exhaust that I suggest getting to go along witt this

so i can't use the headers or the cat with the stock exhaust system? and i have to buy a cat back system now? or rig it to fit mine?

i don't want to have to buy the whole cat back system, then i will be left with 2 cats and not have any need for the other one.

no no..a cat back system exhaust connects to the back of ur Catalyc converter..u have decided to buy 4-2-1 headers witt a high flow cat so ur original cat. is gonna have to b thrown out..the headers connects to the high flow cat (which is really a test pipe by the way) and ur exhaust system whether or not it's brand new connects to the high flow cat.. I would say buy the cat back exhaust system because whats the point of the headers and high flow cat if ur getting restricted by the stock exhaust system..I have the same set up in my 99 si..except I have 4-1 (1 piece) header witt a high flow cat (test pipe) just like urs and a cat back exhaust..good power gains but= HIGHLY ILLEGAL!!!..haha

how does stock pipe ristrict the flow compared to the CB kit?

http://i9.ebayimg.com/02/i/06/de/f8/b0_1_b.JPG
Thats not a cat in the pic?

The piece of piping in the middle on that pic is the one that bolts up to your cat. It's not another cat pictured..Thats a nice system tho..Fireball Tsudo series I like it..it will look good! I personally went with the other Tsudo one. Cat Back systems means that it bolts right up to the back of ur cat. If u didn't go witt a high flow CatBack Exhaust system ur car might not run properly cause it's pointless to have highflow headers and cat and be restricted by ur stock piping..when u install all that sheeit..u need to run it for about a good hour and then re-tighten the bolts to save u trouble down the road.

oh..and another thing..keep all ur stock headers and cat and exhaust for when u go to get it smogged..or I would suggest getting it smogged first so u dont have to worry about it for like 2 years or sumtin like that..haha

the larger piece attached in the middle is the resonator. nothing to do with engine management, just there to quiet it down