Make sure you have solid battery connections & no cheap or dodgy battery changeover switches. Use nyloc nuts on the battery clamps NOT wingnuts. The comments about the laptop & software are valid (or at least the positive comments are) It allows you to "see" into the engine in the comfort of you own home, drive ,shed. You can read/reset faults, adjust various settings etc. I use xd100 with the engines set to xd100, for ultimate protection you can use xd100 on the tcw3 setting. For the amount of oil the engines will use, this will make bugger all difference. The diagnostic cable is easy to make if you know your way around a soldering iron & ebay. The engines are no more susceptible to water in the fuel than any other, show me an engine that will run on water & I'll buy one. Fit good water separators (Racor) & keep the tanks full. I use Evinrude 4+1 fuel conditioner & have never had a problem.
Above all, enjoy the engines, they are the Tescos meatballs