I can't believe this was even a question.
A well sailed 28R should NEVER beat a well sailed 31R boat for boat, period.
I think you misunderstood my question.. I am well aware that a 28R is slower than a 31R.. I was asking if a 28R could ever be customised (a la Cheekee Monkey style) to beat a standard F31R.. examples of mods being stripped out interior, more efficient foils, more sail area..