The ShowDown is just under 30" long, to be able to mount two, you'll need a minimum of a 66" roundbar or a 70" Core or JetStream bar.
Be sure to check that your vehicle is an approved fit before installing, you can check it here.
Maximum boat weight for the Showdown is 80lbs.
If you have additional questions you can contact customer service here, or by phone at 888-925-4621 M-F from 7 to 4 PT.