Straight-pipe stock exhaust improvements?
 

I'm fixing to address the need for an exhaust system but I'm curious if there is any efficiency benefits to just straight-piping (removing DOC & muffler) the stock exhaust? I know there will be much more sound and turbo whine but are there any performance and/or mpg gains doing this? Your advice and suggestions will be appreciated.

*originally posted in wrong forum...

not a lot of new posts here. I pulled my muffler out 5 years ago, never had any problems. sounded better. needed to leave CAT in for inspection purposes. have had lots of egr valve issues in last 5 months. just had 2 changed; 1 for manuf defect but also my egr cooler was "clogged"?? not sure who's giving good advice. not mechanically inclined so I'm stuck

Straight-pipe stock exhaust improvements?
 

I was reading that the new SCR/dpf systems only robs about 15 hp. but looks to me that it could be a potentially costly system to maintain as the truck ages.