I'm a fan of Pepsi for my mid-ride pick-me-up, but a Coke will do. I don't think it's the carbonation which bothers people (who have issues with soda mid-ride) but probably the acidity of the cola. Personally, I chug a can of Pepsi after a mid-ride sandwich, hop on the bike and crank out a monster burp, and I feel great.

As for the salt on your jersey, some people just sweat a lot and lose more salt. (I'm one of them.) It was bad enough after the 200k this weekend that I took a pic of my jersey. When I took it down from the hanger to wash it that evening, the salt was literally flaking off the shoulders. Endurolytes are our friends! Keep the salt intake appropriate or you'll cramp up or risk hyponatremia. (someone mentioned it earlier)