I'd save the 2k and go with the 130. $2K will buy a lot of fuel for those gas sippers. I don't think the economy will change much between the 2 motors as neither will struggle to move a 20. Nice to have nice options.
You could probably save another 2 grand with the 115 and still break 40 knot per hour...
Based on the weight you mentioned, it sounds like your considering the 20" shaft. If you haven't already considered it, you might look at raising the transom and going with a 25" shaft. Much safer, and better resale...