OTF,
There was a thread about this a long time ago. The screws through the rub rail, deck, and hull will strip out or break off. Sections of the rail will loosen and then the deck/hull bond begins to seperate. I replaced a majority of the screws on my 311 with heavier stainless thru-bolts with washers and nylock stop nuts. You can access the ones in the engine compartment and side coaming area pretty easily. You will need to take down the trim in the cabin area and bathroom, and pull the fridge to access the others. There will be a couple you might not be able to get at.
You will need someone to hold the screw head outside while you tighten the nut inside and it will take some interesting contortions of the human body to accomplish this. A 12-pack for one of your smallest friends would be a worthwhile investment! Don't forget to line all the screw heads up identically as they do at the Formula factory (the devil is in the details, right?)!
A pain in the backside, but well worth the time. The whole boat will feel noticeably more solid again. And you won't have to leave three clueless drunk chicks and your beer in the cockpit while you go up on the bow on the way to Put-In-Bay in six foot seas to tie wrap the flailing rub-rail and exposed screws to the deck rail to keep it from gouging the crap out of your gelcoat!