I wouldn't be surprised if there isn't a big performance gain either, but I would be surprised if it does run hotter than SB (not at launch but after the platform matures). Like I said in my earlier post, I'll bet some of those early reviewer BIOS revisions overvolt the CPU to ensure it stays stable (especially with turbo boost). We even see that on mature platforms.
By the platform maturing, do you mean hardware or like... drivers? Meaning, if I buy an IB chip when it comes out, and they make it better later on, (platform "matures") will I be able to reap the benefits of the changes they make? Via software? Or will it end up being a different chip, and I'll be stuck with the hot first edition?