If you're going to the trouble of building a high output forced induction engine, putting in open deck sleeves [which are really just replacements for the stock stuff] is about the dumbest thing you can do. I don't know of any engine builder, myself included, that would feel comfortable doubling or even building triple the power on stock type sleeves on any engine seeing street use.

I know there are people making 400+ HP on stock blocks, although not for long at those levels. A closed deck style sleeve helps incorporate the entire block into the strength of the sleeves, and I wouldn't want the tops of the cylinders having any chance of moving around on any I-4 engine making more than 250 HP. At those power levels, even without detonation, you run the risk of getting such high peak cylinder pressures that you can actually unseat the cylinder from the headgasket, blow it, and then quench the cylinder's interior with coolant, which is what does the most damage.

I would rather be conservative than try to attach a power figure on a turbo build-up for various stages of "necessity".