I just picked up a 2012 silverado and I'm thinking about doing exhaust on it. the way the truck is set up I've got a cat just behind each manifold, then a Y, then a cat, then muffler. I've been considering cutting the pipe just after the first 2 cats, running 2.5 true duals into a H, 2 flowmasters, and then 4" tips. What do you guys think? Do this or get a single aftermarket catback?

 

search, this has been gone over many times, generally flowmasters are crap. Depending on what your future mods are a catback could be just fine, if your going boosted Id try and find a stock exhaust system from a 1500 that came with the 6.2, that system would be 3.5 inches all the way, then replace the muffler with something like a corsa. thats what I would do

 

What he said. ^

 

Keep it a single and go for a straight through muffler design and a 3" kit. Bolt on systems are generally better for moderale power levels because they are designed much better and have high quality bends than most 'custom exhaust'.

Of course when you start to get into serious power you will outgrow the single 3"... but youre a LOOOONG way away from that.