ok this is kinda a long story...
I bought my integra GSR in virginia like 2 years ago as a theft recovery. The catalytic converter on the car at the time was having problems, so i bought some shitty aftermarket one. It didn't fit so i just said screw it and hollowed out the old one (most of Va doesn't have emissions). At this same time i had some money left over so i got a used DC sports header off of ebay. The header also didn't fit. At the time I just assumed that the guy had screwed me over. The reason it didn't fit was that the bottom piece was about 4 in. to long. Rather than going through all the hassle of trying to get my money back I just got someone to cut and reweld the end of the header back on, which worked fine. Now on the DC heaher there was an O2 port on the bottom end, which was cut out in the process of getting the header to fit my car. But this was okay because on my OE header/manifold there was no O2. but there was 2 o2 sensors on the cat (one on each end)

This setup has worked fine for the last two years, however now I am geting my car registered in PA i need to pass emissions. So I bought a Carsound (Magnaflow) Cat [#22639]. I just picked it up today and when I started looking at it i realized it is not gonna fit. There are two differences between the cat on my car and the car sound cat (These are the same reasons the aftermarket one would fit):

1. The angle between the flanges is different, that is if i were to bolt it to the header, the 3 holes in the flanges on the other end would be off by about 20 degrees. however it is the right length.

2. The car sound cat only has an O2 port on the exit of the cat. while the one on my car has one at each end

For starters can you guys fill me in on whether my header is supposed to have an O2 port on itm, and if it is, why the hell didn't mine? I have no reason to believe that the exhaust was not completely OE when i got the car, and yes, I am sure this is a '98 GSR

It is kinda hard to describe the angles of the flanges without pictures, but if anyone knows what is going on please help me out.