[WSSix]

Personally, I love Maggies for the exact reason you specified. They make great street blowers. If you want 600hp crank, that's fairly easy. At the wheels is another story. I'd stay with the blower since you have it already.

What I would do is get in touch with a shop that does FI builds. Tell them your goals and see what cams they recommend. I'm no good at blower cam recommendations. You might be surprised at how small and mild the cam they spec for you ends up being. You should be able to reach 600hp crank with a pulley and cam. I would still prefer to see some head work simply to not push the blower so hard. That's my preference sort of like raising compression. If you jack up the boost, keep an eye on your intake air temps when pushing the motor. You may also need to invest in a water or meth injection kit. Doubtful if you're not beating on it hard and for longer periods but higher boost creates a lot more heat.

Make sure your exhaust is up to the task as well.

For reference, I did an LS1/T56 with a nonintercooled Maggie, so 5.5 psi, with a small blower cam, mild ported LS6 heads, and 1-3/4 inch headers with 3inch exhaust through a Random Tech cats. The result was 550hp at the wheels. Torque was 450-460 at the wheels and very flat. I stopped at 6200rpm and hadn't reached peak HP yet. Fun motor and very easy to drive with the mild cam.

Good luck.