4 low isn't really needed except for extreme circumstances; if you are going to be in one of those circumstances, you'd already know you will need the 4L gearing. Towing: are you going to be doing a lot of towing? the gearing and upgraded radiator will help a lot, even below the 6000lb non-tow package rating.
If you are buying, regardless of towing/offroading, is the tow package gearing - this is the thing that will affect you day to day. The 4L & HD radiator will not affect you one iota.
So, get the FX4 if you think you might need it. Get the tow package if you will be doing hauling, and don't mind the higher gearing on the highway. If it was me, and had the choice and money, I'd get both: rather have them and not need it. If you end up towing more than expected, then the gearing will be to your benefit. If not, then I'm not sure you'd even notice the gearing.
(I have neither in my XLT MAX, but my old vehicle had both abilities: I tow a 4-5000lb trailer occasionally, and do farm work off-roading; nothing strenuous but occasionally 4wd to clear some obstacles, or not tear up the pasture in 2wd. The standard package work fine. People always think they will do more than they actually do).