The following bonuses become available when you complete the corresponding tasks.
Unlock .44 in Safehouse:
Complete 10 gang wars.
Unlock Advanced MG in Safehouse:
Complete 20 gang wars.
Unlock Explosive Shotgun in Safehouse:
Complete 30 gang wars.
Unlock Sticky Bombs in Safehouse:
Complete 40 gang wars.
Unlock Gold SMG in Safehouse:
Complete 50 gang wars.
Unlock Golden Buzzard:
Beat the game to unlock a Golden Buzzard on a heliport over the Booth Tunnel.
Unlock NOOSE APC at construction site:
Kill ALL 50 seagulls.
Unlock Parachute in Safehouse:
Complete 15 base jumps.
Unlock Yellow Super Drop Diamond outside Yusef's Apartment:
Beat the game.
Remove ammo cap:
Achieve 100% completion.
Added by: Sanzano Apr 14th 2010, ID#5706
Super Cheats is an unofficial resource with submissions provided by members of the public. These are not usually tested by us (because there are so many), so please use them at your own risk.