hey yall I have a 00 dx Hatch and I cant figure out what cat converter I need.

I have the Megan Racing Headers and I have the WS2 Worldsport exhaust both for my year and model but on procivic they have multiple size cat converters.

I am getting the magnaflow cat but the choices are either 2.25 inlet/outlet or 2.5 inlet/outlet I thought I needed the 2.5 but I am just wanting to confirm this.

 

did you modify your piping? if not then you will need to get the 2.25