2006 60HP E-tec

What are the differences between the following products (all from BRP)?

2+4 fuel conditioner
engine tuner
fuel system cleaner

I can't get these products in Barbados (dealer refuses to bring them in). The boat is used daily, and I have just switched over to XD100 after using XD50 for the first 1500 hours or so. I use racor filters which I replace every 3 months (300 hours or so). The 50 gallon internal fuel tank tends to get a fair bit of sludge and water condensation which is trapped (I hope 100%) by the filters.

The engine are running great, but I am wondering if I should be using any of the above products to extend engine life/fuel consumption/etc....