1 - 3 lbs would be ok if you raise the fuel pressure, but realize if it runs lean, engine damage will occur. You really need to go through and upgrade the engine and fuel delivery system to handle it, and then get tuner to adjust the parameters. If you run more than a couple lbs boost you will also need a larger MAF, and probably a larger throttle body as well. There is no simple way around it, it will be expensive to do it right. You can cheap out and it might work for a while. I would buy the engine kits, go in and replace the pistons and rods, I would go with stronger head studs, different valves, the whole works. Once you do that, no need to limit yourself to 2-3 lbs., go all the way to 7-12, maybe even more. You need larger injectors to handle the needs of the motor under boost. And the SCT tuners like the Xcal 3 can tell the computer how to handle all the changes.
Plan on upgrading the trans too, even for only a couple lbs, you need a shift kit at least, ideally a stronger torque converter, and better bands and clutches.