I'm currently rolling in around $250k/week, with a tribute of 50%. I've taken over all but 3 fronts, and 3 rackets. I've got two more warehouses to seize, one more shipping hub, and two more compounds (Cuneo and Barzini).

The only weapon I have left to upgrade is my shotgun (which is currently a Level 2). But the Street Sweeper shotgun is a cool $500,000! Hell, the Lev. 3 pistol was $250K!

Some advice, not only do you have to seize as many fronts and rackets as possible, but you wanna occasionally rob a bank, too. My bank of choice is in northern Midtown. There's a Barzini hotel nearby that you can take over, with a safehouse inside. It's the most expensive safehouse in the game though, running you $125,000 I think.

Anyway, the bank in northern Midtown is a $50,000 bank. Before you rob it, head over to the police station and pay off the chief ($1,000). He'll keep the cops off your ass as long as you don't kill any officers during the heist. Head down to the basement of the bank, kill the guard that's guarding the door. Then immediately turn around and kill the guard that appears behind you, and kill any other guards coming your way. Then go through the door to the vault, plant some dynamite, and take cover. Grab the loot, and haul ass back to your nearest safehouse. You just made a quick $50K!