BimmerBoost would beg to differ. There are drawbacks especially with flanged sleeves as when material is removed from the block to install the sleeves the rigidity is compromised. That is simply the experience with my own sleeved S65 V8 running high boost and Gintani's experience with various sleeved blocks.
The approach taken for the BimmerBoost.com E92 M3 now is going with a high strength chromoly bed plate to brace and reinforce the block while leaving the bore alone. BimmerBoost previewed this bedplate in an article last year and now you can see the finished design and how it compares to the factory.
There will no doubt be people saying sleeves are the way to go. They are welcome to try. The factory block without sleeves is currently supporting over 700 horsepower to the wheels.
There are obviously going to be upgrades other than just this brace but take into account what AMS says here:
What will an S65 V8 do with a reinforced block, forged crank, forged internals, and turbos? Well, we are going to find out.