There are plenty of no drill kits out there and I would not weld or drill on a 3rd or 4th gen (with some exceptions) If you go to the
http://m.dodge.com/bodybuilder/ it will have the directions for where and how to drill. But why drill if you don't have to. If a Dealer told me there was "no problems" with drilling the frame I would find another dealer because there are problems! Lets face it, you don't know who is going to install you kit once it goes into the shop, and a LOT of hacks call themselves mechanics.
Just my opinion, you can do whatever you want.
From the body builder site for 2005 ram
Holes
Holes are not to be drilled in the top or bottom of the
frame rails. Holes to mount out-riggers, brackets, and
supports must be drilled in the web (vertical sides) of the
frame rail with the following restrictions:
1. Hole diameter should not exceed 20 mm (0. 75 in. ).
2. Material between edge of hole and top or bottom of the
frame rail must not be less than 40 mm (1. 60 in. ).
3. The minimum edge distance between any two (2)
holes must be larger than twice the diameter of the
larger hole.
4. Any thru-fastener that torques down on both external
surfaces of the rail must use an internal spacer to
prevent crushing the rail tube.
5. All holes should be drilled in the frame using
appropriate drilling practice and safety precautions.
6. Avoid drilling holes near the fuel tank, fuel and brake
lines and other lines and wires to avoid damage to
them.