I wouldn't have bothered if I had an E8600. High end quads are still expensive, can't see how the cost can be justified for an upgrade that won't make much of a difference.
If you really want a quad core CPU for some reason, you might want to look into modding your mobo to accept socket 771 CPU:s instead. Socket 771 Xeons can be picked up for peanuts, guess the market for selling server grade CPU:s is quite limited. Did the mod on my Asus P5B Deluxe, and put a Xeon X5470 in it. Works like a charm, and it seems to overclock extremely well. Had it running stable at 4 GHz on air cooling when testing how far it could be taken. The 12 MB cache doesn't hurt either.
In short you'll need to cut away the socket's keying, glue a sticker to the Xeon, patch a bios image with the correct microcode for whatever stepping CPU you got if you can't find a prepatched one, and flash it. Then you just install the Xeon like any other CPU. Here's a comprehensive guide if you're interested.