IMHO what it really all boils down to is this. If you are really that worried about major failures, and a major repair would put a major crimp in your family budget, then perhaps you should either buy a much more reliable product or leave the Harley stock and hope H-D doesn't still try to screw you around on warranty issues. Trust me, they screw many people around on stuff that has nothing to do with customer modifications at all. Things like defective chrome and paint come to mind, as well as those mechanical things that they claim are "normal" but are in fact not acceptable.
As for the ESP, I've stated my opinion many times in the past but the short version is forget it, put the money in a safe investment instead, and if you do have a repair or two come up after the factory warranty then use that invested money to make the repair. If you get lucky and have no repairs, you still have all the money plus any investment returns. On the other side of the equation, if you pay nearly two grand for an ESP and don't have at least two grand worth of repairs, the ESP folks have that money in their pocket and you'll be out two grand for nothing.
Jerry