I've got the new system on. Works pretty good, but is a little louder than I expected. I don't think I care for the single 3 inch system. This will definitely be my last single system. The sound is a little more brappy than it would have been with duals, so later on I may get another Flowmaster 2 into 1 and drop the rear pipes to dual 2.25s with glasspacks to tone the sound down some. I hate saying this, but I think I've become accustomed to a nice, quiet exhaust .
Performance, on the other hand, is a whole different story. Way above where it was. There was a small improvement in fuel economy, but not enough to justify the expense. I've got another school coming up so will be off for a bit, but I'm thinking of trying an Ed Wright chip tuned for fuel economy when I get back.
New system is a set of Summit headers, Stainless Works chambered muffler, a Flowmaster 2 into 1, and had to have the muffler shop add a glasspack with a turndown in the back due to the obnoxious noise the system made with just the one muffler. Tone is great, just has that braap to it that I don't care for, that the dual 2.25s should take care of should I decide to mess with it later. This exhaust will definitely last till the truck's first engine swap, which will sadly be a few years down the road.