What is the advantage of an 8 speed and a tow package on a 2015 Dodge Ram

If you do not tow, no advantage whatsoever. The tow package is an auxiliary transmission cooler, a engine oil cooler, stiffer suspension, and I'm not sure what else. But gets expensive if not needed. The 8-speed is kinda cool, but again only really needed for towing, and I mean towing very heavy loads. There are NO disadvantages. Only cost.

definite advantage transmission cooler better for transmission bigger battery and alternator, usually not to much more i dnt know the cost , plus if you would ever need it it is there , iget it even if we will not need it ,like her van and durango