Without knowing the specifications on your TT, or your truck it is hard to give a good informed opinion.
However, as a general rule of thumb, your GMC 1/2 ton shouldn't have any issues towing most TT up to 25 foot. As I said, this is a general rule of thumb even though the industry is building these ultra lites with weights well in the range of the 150/1500 class pickups. The only issue then becomes the length of the trailer being two long for a lightweight soft suspension truck.
However, back on topic. My opinion, is get a WDH. It will definitely help matters and certainly won't hurt. In addition, you may look for one with integrated sway control or the add on anti sway bar(s). It certainly won't hurt anything and it will make your towing experience much more enjoyable and comfortable.
2015 White Hawk 25BHS Glacier Package
2004 Dodge Ram 2500, 5.7 Hemi, 5Spd Manual
2008 Arctic Cat M1000 SnoPro
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