This is a general gameplay mod package that integrates a number of modded parts of the game. It even has it's own thread (like half the others)

http://www.videogamemods.com/justcause2/index.php/forum?func=view&catid=14&id=812

Note: I changed it to a rar because too many people don't get small unpack. Now officially a .rar file. Install the dropzone into your install or copy the files out of it. Do not place this dropzone folder inside your own dropzone folder. That's stupid.

::Installation and Removal::

To install simply copy the contents of this dropzone folder into your dropzone folder. If you do not have a dropzone folder, you create it within the just cause install folder so that the path is C:\...\Justcause2\Dropzone.

Most of the mods may be installed or uninstalled without affecting other mods.

- Weapons.bin
- Weapon_upgrades.bin
- Grappleparams.bin

These three are all interconnected, and if you wish to remove one you must remove the other two as well.

- Camera_settings.bin
- Camera_defaults.bin

These two are also interconnected, and must be removed or installed together. All files are independent of each other unless noted above.  

Changes by file

::Moon_full_dif.dds::

- Majora's Mask Moon

::sportscar.eez::

- Sports car speed slightly increased, traction slightly increased, acceleration slightly increased, health vastly increased.

::atv.eez::

- Same general changes as the sports car.

::barge.eez::

- speedbarge mod from vehicles

::AIparams.bin::

- AI reaction to impulse forces increased. Ragolls will generally fly a good bit further

::blackmarket.bin::

- Prices for all items lowered to 10% of normal

- Panay's rocket launcher and bubble gun/explosive minigun added (see weapons.bin for bubble gun mod)

- upgrade prices reduced to 5, 5, 10, 10, and 15 for the progressive level upgrades.

::Cameral_defaults and camera_settings::

- Disables camera auto-center in vehicles

::Explosion_triggered_mine.bin::

Triggered mine explosion graphic changed to that of a firebomb (small mushroom cloud)

::grapplingparams.bin::

- Grapple range extended to 100x normal

- Grapple speed increased, 40 to 50 mph while chute deployed, 40 to 100 mph for normal grappling.

- Grapple melee impulse increased, you'll knock cars around and npcs will go flying

- Grapple pull strength increased, you'll pull enemies into the air, perfect for constant juggle kills

::Heatspawn.bin::

- Military presence increased at all levels, most spawns increased by one or two per heat level. Chopper respawn time decreased for heat 3-5, boat spawns increased at all heat levels to provide lots of pursuit at high heat levels. Heat 5 is something to be avoided, heat in general will have more gameplay impact.

::Player.bin::

- Damage resistance increased

::sheldonservice.bin::

- Black Market Cutscenes disabled

::weapon_upgrades.bin::

- Revolver damage, stability, impulse, fire rate increased

- assault rifle damage, stability, impulse increased

- Bubble gun damage, stability, impulse, magazine capacity increased

::weapons.bin::

- Shotgun damage per pellet decreased, pellet number increased, for both shotguns. More lightshow, about the same damage.

- bubble gun turned into 2 handed minigun held like an assault rifle. has explosive rounds, does high damage.

- grapple range increased (part of grapplingparams.bin mod)

- Assault rifle made 1 handed

- Big Shotgun made 1 handed

- Range adjusted on NPC hit values to prevent assault rifle goons from hitting you from 200 yards away.

- Panay's rocket launcher changed to reflect more realitstic values.

- Explosive range on grenade increased from 5.5 to 7.25 feet at level 6. C4 increased to 10 feet at level 6. Rocket launcher explosive range increased from 3.5 to 5.5 feet in radius. 

::Worldsim.bin::

- General spawns increased. Land vehicle spawn times shortened, and vehicle variety increased. Plane spawns greatly increased, you'll often see tons of planes flying all over the place, and get random chaos from planes colliding with crap when you're at low atlitudes.