Hello! It's general knowledge that both aftermarket O2 Housings and Downpipes will be less restrictive in the airflow department. Optimally, you'd have to buy both parts in order to benefit from this; but STM has a product that has integrated the O2 housing and Downpipe into one piece, take a look!

Of course they have this pipe with an O2 Dump as well for people who prefer that. My question is: What's the point? Would it be better to purchase this all in one pipe from a performance stand-point? I'd like to know what anyone thinks/knows. I'm sorry if this information has been covered before!

 

It makes the car suck to work on having it all one piece

JMFab makes a 2 piece O2/downpipe comber that is full 3" and uses a vband.