Various Features

 Space Docker car
Successfully complete the "Far Out" mission for the Omega stranger (he becomes available after completing the "Fame Or Shame" main mission) in east Sandy Shores by collecting all 50 spaceship parts in Grand Theft Auto 5 to unlock the Space Docker (alien) car. This car is loaded with alien technology, including two large booster jets.

Alternate costumes
Successfully complete the final mission in the main storyline to unlock mission-specific costumes for all three characters, including the black outfits from stealth missions, guard uniforms from the final mission, and police uniforms. To unlock all shirts, get a 100% game completion.

Ammu-Nation discounts
Successfully complete all Gun Range challenges with Bronze medals to get a 10 percent discount at Ammu-Nation stores. Successfully complete all Gun Range challenges with Silver medals to get a 15 percent discount at Ammu-Nation stores. Successfully complete all Gun Range challenges with Gold medals to get a 25 percent discount at Ammu-Nation stores. Note: Discounts are attached to each character. Thus, getting all Gold medals with Michael will only allow him to get the 25 percent discount.

LifeInvader unlockables
To get bonus customizations, discounts, and free items for Michael, Franklin, and Trevor, go to Rockstar's LifeInvader social network, and click the "Stalk" button on the page. Sign into LifeInvader with your Social Club name and password. Then, different pages will appear randomly after refreshing. Click the "Stalk" button on each one to unlock something new for use in GTA 5. For example, to get a free haircut and unlock additional hairstyles, go to Herr Kutz Barber, and click the "Stalk" button. The following is a list of all unlockables for clicking the "Stalk" button on each LifeInvader page:
Elitas Travel: 10% off your first purchase through ElitasTravel.com
Herr Kutz Barber: First haircut free, and extra hairstyles
InkInc.: First tattoo free
Legendary Motorsport: 10% off your first purchase through their online showroom
Los Santos Customs: Free paint job
Redwood Cigarettes: 10% off your first visit to a participating hospital
Sprunk: Free can of Sprunk
Warstock Cache & Carry: 10% off your first purchase in-store