Towing Questions

[fishstu]

I am a complete newbie to trucks and towing a 20-foot boat.

My boat is a 20 Seacraft on an Alum Loadmaster dual axle Trailer model 19.21.6, Kodiak disc brakes on one axle with a TITAN model 60 surg-o-matic hydraulic brake actuator.

My tow vehicle is a 2005 Toyota Tundra double cab, V-8 with factory fitted tow package (wired 7-pin plug, heavy-duty tow hitch, and 130-amp alternator.

I found an Electric Brake Controller Connector harness in the glove box. Do I need an Electric brake controller, what are the advantages in having one?

Is it a good idea to fit rear adjustable air shocks and what are the advantages/disadvantages to fitting disc brakes on the second axle- more braking I know but does a 3000 lb load need it and is it one more thing to go wrong?
Do brake-flushing kits work well and would you recommend fitting one to my rig?

I tow 200 plus mile and would like to hear experienced boat towers recommendations to make my rig as safe as possible.

Many Thanks