How to dominate the Arena...
Rockstar announced and subsequently released the new Arena War DLC for Grand Theft Auto Online with little warning.
The new content involves an action-packed arena with nine game modes framed as a TV show that makes a destruction derby pale in comparison. Here are a few useful tips on how to get the most out of Arena War, how to gain AP (Arena Points) the quickest, and more.
The Arena Workshop
First of all, let's look at the Arena Workshop. This is the current equivalent of the Office/Clubhouse/Bunker/whatever new property is introduced by the DLC the purchase of which is necessary to play the content. It costs GTA$ 995,000 — 4,365,000 and unlocks the Career progression. Without buying the Arena workshop you can still access the new game modes, but most of the new content won't be accessible.
By purchasing the Arena Workshop, you can begin to earn and spend AP. Additionally, there are a number of upgrades that can be applied to the Workshop. These include living quarters, which allow you to spawn here, two additional garage levels with 10 slots each, a Weapons Expert which is the same thing as the Weapons station in the MOC and Avenger, a Benny's mechanic which is the same as Benny's custom shop, and finally an Arena Mechanic.
Of these, only the Arena Mechanic is actually necessary. If you already have a MOC or Avenger, the weapons expert is superfluous, and Benny's is nearby. The only reason you'd buy all of these upgrades is if the luxury of having everything in one location is important to you. You can also alter the decoration and design of the workshop. In the corner, you'll find the RC Bandito workshop, which specifically serves as a place to customize and upgrade your RC Bandito vehicle.
Vehicles

The Arena Mechanic, however, allows you to customize the 12 new Arena vehicles. There is no other way to upgrade or customize them. There are 3 cosmetic styles for all Arena Vehicles (Apocalypse, Future Shock and Nightmare) which don't affect performance. Upgrades unlocked with AP do have an effect on the vehicle's stats and abilities, however.
Speaking of vehicles, it's become very clear, very quickly, which Arena vehicle is the top dog — the Deathbike. It's faster than the other vehicles and has a number of odd advantages such as being highly resistant to flamethrower weapons. It isn't clear just how much of the Deathbike's advantages are intentional since vehicles considered OP in the past have turned out to be bugged.
Additionally, 8 special vehicles can be unlocked by climbing the Tier ladder for Arena Sponsorships. Each individual tier rewards you with a random discount on new content, however at specific tiers, the following vehicles are unlocked.