3" downpipe or full exhaust which is better on my 7.3 power stroke?
Which is which?
Any examples and pics illustrating each one would be appreciated
Learning thanks

 

Full system 4 or 5

 

The factory downpipe is the most restrictive part of the factory exhaust. It is flat as a pancake... Replacing that with a 3" round downpipe is where all the benefits come from. Anything after that is just for sound... You can easily just replace the downpipe or you can buy an entire system. It won't make any difference except for sound. The important part is just getting rid of the factory downpipe...