I thought so too haha! Use the part numbers listed on the thread it will be 1.75" just like kyle675osu said. You can always call cone engineering too, they only take phone orders anyway and they know our set up. Where abouts in Rich are you at?
See you don't have any friends yet, so I figured since I'm in pinole and your in Richmond I might as well friend ya right. Did you get your merge collector done yet?