If by "traditional" spaghetti sauce you mean Bolognese sauce, I would doubt the mushrooms, but I'd agree with wine twice (as stated). Maybe Paprika. Some might use a bit of milk or cream. A little salt. A lot of tomato puree. I use a lot (relatively) of chilli, some Worcestershire sauce, and a dash of lemon or lime. An easy cheat to save quantifying the small amounts of sugar and salt is a squirt of tomato sauce (really has to be Heinz). Oh, and don't forget the meat!

A pretty fair analogue for what I do to traditional songs, really - muck about with them, boogie them up a bit, and try to find an easy way to play them! But don't forget the bits that have always been there.