I think on my 01. 5 the snowplow prep package had stronger front coil springs, adjustable spring height, HD transfer case (241HD) and possibly higher amp alternator, but not positive on the alternator, maybe a skid plate. Mine came on my truck off the lot so I am not up on what would have been involved in ordering it.
Not sure if you can order he actual plow from Dodge or not.
When I am under my truck I dont think that there is anything else that would interfer with a new bumper. I would think that any plow would come with its own sub frame/mount since there are so many different brands/years/configurations.
hope this helps,
J-