What car is the fastest (when upgraded) in GTA V and where can I find it?
However I prefer the Overflod Entity XF as it has significantly better acceleration and traction - which matters more than top speed IMO.
Both cars will occasionally spawn in the game world (generally around the richer areas of Los Santos) but if you do steal one you cannot "own" it. The Adder spawns frequently in front of Sessanta Nove at Portola Drive, Rockford Hills.
To own one of these cars you need to buy them from Legendarymotorsport.net - and they're expensive with the Adder at $1,000,000 and the Entity XF at $795,000
It's reported that you can own the Entity XF via the mission "I Fought the Law" but this seems like an exploit of sorts.
And if you want a fast 4 seater car check out my question about that here: What is the fastest 4 seater car in Grand Theft Auto 5?
The current fastest car in GTA V story mode is the Vapid Pißwasser Dominator.* It is only available in the Enhanced Version of the game (PC, PS4, and Xbox One versions). It can be acquired by winning the third stock car race.
* Not counting GTA Online cars that can only be used in story mode if the game is modded.
The second fastest car is the Truffade Z-Type. On the PS3 and Xbox 360 versions, the Z-Type is the fastest car since the Pißwasser Dominator cannot be acquired on those versions. The third fastest car is the Truffade Adder. This is according to vehicle testing by Broughy, who tests vehicle top speed by driving them on a track. Broughy's testing takes the game's physics into account, as opposed to just getting the speed stat from the game files which is less indicative of actual top speed.
The cars' stats:
|Vapid Pißwasser Dominator||Truffade Z-Type||Truffade Adder|
|Top Speed - Real (Broughy)||126.50 mph (203.58 km/h)||126.25 mph (203.18 km/h)||124.75 mph (200.77 km/h)|
|Top Speed (Game Files)||91.34 mph (147.00 km/h)||95.69 mph (154.00 km/h)||99.42 mph (160.00 km/h)|
|Story mode price||n/a||$10,000,000||$1,000,000|