Is paying the extra money for 5" exhaust over 4" worth it?

 

5" is a pain in the neck to fit and rather big.. but hey if you want a deeper louder truck the fives the way to go but the 4" will be easier to work on.

 

Do you have to have a 4" down pipe on duramaxs?
Is a full 4" system sufficient with high hp?

 

yes with 3" your egts more then likely be high if your going high hp.. you probably have to find a 4" downpipe and custom bracket it yourself though. Xtreme Diesel Peformance should have one. If not try Pinnicle Performance Exhaust.

 

You could try matching title to content of thread

 

and that too

 

Exactly,

what's up with that!