The muffler delete might have helped with power on the older trucks. Doing this on a 2004.5 and up with factory 4" exhaust from the turbo back seems like a waste of money.
I always recommend a steering stabilizer for Dodge trucks. The steering box can flex on the frame. This translates to wondering on the road.
Genos GarageHave him check under the hood for a lube sticker for the front driveshaft. Some truck front drivelines do not require lubrication. Mine does. This lube job requires a needle fitting for the grease gun. Many dealers including mine do NOT lube this fitting with a normal oil change. They should.
Gauges help (boost,egt,fuel pressure,tranny temp). Always use quality filters. Avoid cheap filters that do not "Meet or Exceed OE specifications". As mentioned be sure the computer updates are completed.