first thing to consider.Is the trailer on a fondation.If not, you will have to do some serious structural framing of the base/floor so that in winter thaw,both the old and new sections move together as a single unit.
Great thread.
I supose you would have to look also at availability of parts also.Fuel efficiancy is a definate advantage to newer, as well as pollution concerns,oil and fuel leakage.For those 2 reasons alone, i would probably consider the newer motor over the older one.Just my uneducated opinion though
why dont you hook up the stereo through the ignition switch.Then,like a car,when you switch the ignition off, everything else is swwitched off too. Can this even be done with a boat.
A draw could be a short circuit, loose connection,faulty wiring,faulty switch,etc.Determine which circuit is causing the drain, then check everything on that circuit for the problem.