I'm about to be getting a 2014 Sierra 1500 and was wondering what a good exhaust set up would be for it or best muffler choices for the new sierras

 

They're no different than 99-13 trucks. Going to sound pretty much the same as those trucks with whatever exhaust is on them. Exhaust options are covered extensively on this forum. There's also a Gen 5 Sierra/Silverado (2014+) facebook group that has some info on it

 

Flowmaster offers several great options for your truck. Here is a link to a few of the Cat-back systems that we produce for your vehicle. Each kit has a video link next to it so that you can put on some headphones and see if it will meet your requirements. Good luck!

 

Stock piping I believe is 2.75" inch stainless, so I cut off stock stuff and had a 3" inlet 3" outlet stainless magnaflow welded in, then 3" piping to stock 4" tip. Sounds perfect IMO. Quite at idle and cruising, yet aggressive when getting on it.

 

Post up a sound clip.