Re-rigging my 600hp's from my old trs boat to a bravo boat. Is there any real advantage or disadvantage to using alum flywheels versus steel ones?

Go with the steel flywheel. The engine needs the enertia of the heavier flywheel to help keep the engine running when you put it in gear. When you go in gear, you put a ton of load on the engine in a split second. It needs all the help it can get to stay running. That heavier flywheel is harder to stop from turning than a lighter aluminum flywheel. I actually use a really heavy billet steel flywheel when I know the engine is going in a larger, heavier boat. Off the top of my head, I think it's just over 50 lbs.
Eddie

Thank you, makes perfect sense.

BW do you hve any pics of you engine rigger? I have a trs set up and I cant for the life of me figuer out where the bracket gets bolted to.
-Mike