on my old car i had an ebay header with a 2in collector and an ebay test pipe that i assume was geared for the standard DC style 1 7/8" collector because it just didnt seat right on it. Now for my new car i have an edelbrock header that also has a 2in collector and i want something thats gonna be a direct fit. I contacted VRS because i will be ordering a tubing kit from them and they can make me a custom test pipe with an o2 bung for 70 bucks plus shipping. 2 problems, one being in MD and having an OBD2 car (its a 2000 civic) i get emissions every 2 years that includes a visual inspection so i have to have something resembling a cat. I know i can weld 2 heat shields together but i'd rather not. second is i really do not want to pay 80 bucks for a test pipe. Can anyone suggest to me what i can do to get something to fit the collector properly? I don't mind having to weld a flange onto a cat. VRS was going to have the pipe have the 2in donut flange and taper to 2.25in to match the rest of the system

 

that's not a bad price. another way would be to just hack the flanges off of the cat, buy a piece of pipe that u need with the right diameter and weld away. when ur done, u can bore out the flange from the cat that way it's the same diameter as ur header.