I have a 5th gen DX.

It has a Megan 4-2-1 header that is made for EX, an ebay test pipe, and an Apex-i WS2 made for an EX. The header bolts on since it's a d series, but there are some fitment issues with the exhaust.

At first, I had another exhaust that was made for EX on the car, with stock header/exhaust manifold and stock catalytic converter. I put on the Megan header, and my exhaust began having fitment issues. I think it's because it was made for an EX, and i had noticed it was a little different fitment than stock at the end of the downpipe, like it was shorter. So then, I switched the catalytic converter to a test pipe, and still had rattling and whatnot.Then recently i switched from the ebay exhaust to an Apex-i WS2. I have also replaced the rubber hanger things with polyeurethane ones. I am going to buy a new catalytic converter as mine was in pretty poor condition.

Since I have the EX header, and EX exhaust, will installing the EX catalytic converter fix my fitment issues?

Or is it the same as the DX catalytic converter?