Do yourself a favor, anything you build that gets attached to your trucks frame, should not be welded into place. Take the extra time it requires to make brackets that bolt into place. Since you have a newer truck, this will require more effort then if it was on and older one. The new hydro-formed frames will require that you use spacers so that the frame is not allowed to be pulled into itself. This is a pain, but can be done. Just go into the project knowing it will take longer and cost more then it might have on another type of frame.
The debate about these Hydro-formed frames is funny. Dodge would like to make everyone think they they are much stronger and the new process is a step forward from the past way of building a truck. But the fact is they are only cheaper to build. After all that is what Dodge bases most of their decisions on, how much will they save per unit. The advertisements are very misleading, they say they are stronger, offer more rigidity. This is true to a point, it all depends on what figures you are looking at. Hydro-Forming a frame rail is simple, quick, makes for less welds and saves time and MONEY. This is why they do it, not because it is any stronger, it is just cheaper. And when they stout about how strong they are, they are comparing the similar size and thickness metal against one that is not boxed or formed. Sure give me a piece of boxed steel tubing and it will be STRONGER then a similar piece of metal that is not a tube, but is it any better? Depends on the application. The old first and second generation trucks were very stout, but pound for pound the new style trucks offer much more rigidity. This is great, it makes the truck handle better on the road, and saves weight which should translate into fuel savings down the road. Is it stronger I say NO. Strength and durability are two key factors any HD truck ought to exhibit, did they build the new frames stronger or make them more durable? NO, they built them lighter, and they built them with more torsional rigidity, which may or may not be a good thing, all depends how you use your truck. If you never haul much and always drive on the pavement, it might be a Good thing. But, if you tow heavy, use your truck in Fields, and UN-paved ares if might not be so good. The new frames are made of thiner metal, they have been formed and welded. In a perfect environment they may appear to be better, but in the real world they fall short. The deal about drilling the frames is real, they are worried about about people drilling through them to attach pieces without properly backing up the frame rails. The reason is that if you were to bore a 1/2" hole through the rail and then secure a piece by using a bolt that extends Thur the rail to a nut on the other side, when you tightened the nut it will draw the frame rail in. This sounds like no big deal to some, but is substantially weakens the frame. Think of a aluminum can, if the can is perfect, and has no dents it can withstand a fair amount of pressure, pushing from the top and bottom to-wards each other. But , make a small indent on any side and the can collapses toward that side with only a small amount of pressure. Mot implying that the new frames are week as soda pop cans, but you can maybe see the similarities. The welding has two problems. The new frames are very thin, it takes much more skill to weld two very different thicknesses of metal. Before your frames were 1/4" thick and most fabricated pieces were 3/16" to 1/4", not a problem for most welders. It is very much more difficult to properly attach pieces to the new frames. Second, is the frame itself. These frames have undergone under gone the hydro-forming process, they have been bent, welded on and then heat treated. When you go to weld on the frame, it will under go a very intense heat cycle. On other types of frames, that may or may not of been so bad, but on these it may very well result in cracks. The combination of thin metal, stress of forming, and your welding may very well prove fatal. The new combination of light weight frames on HD trucks is causing many to wonder. The aftermarket, has been very slow to respond to anything that might affect the frames. Heavy duty body makers, like Ohio Truck are having problems with the trucks they convert. Dodge isn't the only ones, Ford to is starting to having problems. For you and your truck's best interest, I would re-frame for doing anything which might hurt the longevity or warranty of your truck.