1) Yes but that price is high.
2} I quote Pkoronix: "A few months ago, AMD refined their Socket 939 line of processors with the E3 and E4 revisions, codenamed Venice and San Diego, respectively, to replace the D0 Winchester. The Venice and San Diego features the improved memory controller, and most notably, AMD doubled the amount of L2 Cache for the San Diego compared to its Venice counterpart. The San Diego immediately attracted large attention among the enthusiast crowd for its enormous L2 cache; in fact, the Athlon 64 FX-57 is based upon the San Diego. While the San Diego looks great on paper, premium performance also comes at a premium price, and the cheapest San Diego, the 3700+ at 2.2GHz, runs around $330, while a Venice 3500+ running at the same clock speed is $275, and the cheaper versions of Venice 3200+ or 3000+ often overclock easily to 2.6GHz and beyond. Is the price premium justified? Does the extra 1MB L2 Cache help that much in real world performance? Just how well do these two cores compare clock-for-clock? In this review we will be running two of these CPUs at 2.0, 2.2, and 2.6GHz to see the performance difference between the two AMD cores."
3} Nope.
4} About $5-10 too much.
5} They are all ok, for a show-off case, I like this one
Kandolf
For a more reasonable case I like these
Lian Li