Those are not cats they are resonators....it may say that its cats in the title but OBX y-pipes have resonators to get u the flow of headers at a quieter level than straight pipes .. Those resonators help u to pass visual inspections like here in sth louisiana and is quiet enough they believe they are high flowcats

 

Welcome to the forum!

If you'd actually checked the link the OP posted, and read the link, you'd learn that OBX headers can now be had with actual high flow cats. Here's a quote from the link...

Product Description:
OBX High performance racing headers are made out of pure SUS-304 stainless steel. Dyno tested at low end and top speed to increase horsepower. Precision mandrel-bend to enhance exhaust gas flow. These five piece type headers are easy to install. Value-added bolt-on headers for any racing sport performance enthusiast.
•Includes all parts shown in pictures below

•THIS HEADER SET COMES WITH ACTUAL HIGH FLOW CATS AND NOT THE CHEAPER VERSION FROM OBX WITH HOLLOW RESONATORS!

•Dyno tested and proven

•Direct bolt-on without modification

•T-304 stainless steel mandrel bend for ultra fast flow

•CNC machine flanges with TIG and MIG welded construction

•Utilizes factory 02 sensor position

•Gaskets and hardware included

•Lifetime warranty from manufacturer defects