Curious what the gain will be switching to the Ultegra cassette? Other than a few grams do you gain anything?

For the tires I vote the 4000s also. Been running them for thousands of miles and even through the nasty sand and gravel mess of the winter roads they have held up fine. At most I've had one flat in over 3000 miles on mine. I did notice a few gouged holes in the pair on my winter/rain bike but no flats. They roll so nice.