While not a 2013, my 2012 F450, I have put Firestone Riderite's in and onboard Viair 10007 compressor the Reese signature 18K 5th wheel hitch a LineX bed liner weathertech floor liners dual color GT seat covers and (forget brand) the smoked Window Deflectors and headrest DVD players for the kids.
I may change out the front speakers with a pair I already have but the stock pretty much sucks as was mentioned above. I will say the nav had a big improvement with the new 13's that's for sure. WAY more usable!
I have not had any issues with the drive train/exhaust but I only have 4k on the truck and only use it for camping/family outings.
I do really like the truck though.