Airflow Direction

I am fairly new at the whole car thing. I am looking to put some parts on my 03 Max and wanted to make sure I had things straight. The Airflow goes in through the intake, to the engine, through the headers, into the y-pipe, slows down passing through the cat conv, down the mid-pipe and finally out the muffler. Does that sound right? Any corrections would be greatly appreciated.

thats the rough basic idea of how it goes.