The front one is pretty beefy, much bigger than the rear one stock. My guess is because thats where most of the weight is so ram had to make it bigger. Also Hellwig does not make a front sway bar for the rams. I recall reading something from Hellwig on why they dont make a front sway bar, it was something along the lines of "the stock one is good enough"
There are people on here that have swapped out the front sway bar bushings for polyurethane ones and report small gains in handling, not as much as the hellwig bar does though.