Car spawner, limit and delete the car after they left? ^

I would create a table which would store current spawned car of the player, with that you can check if gamer has spawned car or if he does not. For removing car when player leaves you can use Players.PlayerRemoving event which fires when gamer is leaving.

First of all, when you fire remote event to the server, you don't need to specify the LocalPlayer as it automatically fires as the first parameter, also FindFirstChild does not server purpose in it so you should remove it.

local rep = game:GetService("ReplicatedStorage")
local event = rep.VWPassat

script.Parent.MouseButton1Click:Connect(function()
	event:FireServer()
end)

In the server script you should implement the structure because it is best way to stop exploiters that want to cheat.

local rep = game:GetService("ReplicatedStorage")
local ServerStorage = game:GetService("ServerStorage")
local Players = game:GetService("Players")

local event = rep.VWPassat -- your RemoteEvent

-- Cars owned by players will be stored in here
local Cars = {}

local function CreateCar(plr)
	-- This will stop the function and return if player has been found
	-- in the table with cars, means he has car spawned already
	if Cars[plr.UserId] then
		print("Gamer has already car spawned")
		return
	end
	
	if plr.TeamColor == BrickColor.new("Really blue") -- your team color
	then
		local clone = ServerStorage.VWPassat:Clone()
		clone.Parent = workspace
		
		-- I don't know what this does but i assume it works for you
		-- so i won't touch it
		clone:MakeJoints()
		
		-- This will save variable of the gamer to the cars table so next time
		-- he tries to spawn a cat it will see that he has already spawned it
		Cars[plr.UserId] = clone
	else
		print("Not on the correct team") -- if you want an error message or something do it here
	end
end

local function RemoveCar(Client)
	if Client then
		local Car = Cars[Client.UserId]
			
		if Car then
			Cars[Client.UserId] = nil
			Car:Destroy()
		end
	end
end

local function OnClientRemoving(Client)
	-- When player leaves, this will check if gamer has car spawned in the
	-- table and if he does, it will destroy the car and remove it from table
	RemoveCar(Client)
end

Players.PlayerRemoving:Connect(OnClientRemoving)
event.OnServerEvent:Connect(CreateCar)

Make sure not to use WaitForChild on the server as the Instances are always replicated there so indexing is just enough, if you are not sure that Instance is there then use it no problem.

Now you have table Cars which is list of all cars that are spawned, if you want to destroy the car on click, you will need to fire remote event from the client and on the server and then call the RemoveCar function which will find the car in the table and destroy it. Example

local function OnDestroyCar(Client)
	RemoveCar(Client)
end

-- Example RemoteEvent named DestroyCar
DestroyCar.OnServerEvent:Connect(OnDestroyCar)