Can exploiters take advantage of this script?

I asked this question yesterday but never received a solution so I am going to ask again. I am really new to scripting and I am making a speed run game that will start the player's timer on their GUI when they touch a Part. The timer is saved as a leaderstat and I am using remote events to add to the timer. The touch event is in the player GUI and the calculations for the player's time are in the server script. Again, I am pretty new to scripting so is this a valid way of scripting my game while also preventing exploiters from tampering with their speed run times? Any help would be greatly appreciated

Local Script inside player's GUI

local ReplicatedStorage = game:GetService("ReplicatedStorage")

local remoteEvent = ReplicatedStorage:WaitForChild("ShowTime")
local Clear = ReplicatedStorage:WaitForChild("ClearTimeran")
local Replace = ReplicatedStorage:WaitForChild("Replace")


local SpeedBrick = workspace.RunBlock
local EndBrick = workspace.EndBlock

local go = true
local db = false
SpeedBrick.Touched:Connect(function(hit)
	local startplayer = game:GetService("Players"):GetPlayerFromCharacter(hit.Parent)
	if startplayer ~= nil and startplayer ==  game:GetService("Players").LocalPlayer then
		if db == false then
			db = true
			Clear:FireServer()
			repeat
				wait(0.1)
				remoteEvent:FireServer()

				---SHOWING ON GUI---
				local player = script.Parent.Parent.Parent.Parent.Parent

				local leaderstats = player:WaitForChild("leaderstats")
				local stat = leaderstats:WaitForChild("runningtime") 
				local besttime = leaderstats:WaitForChild("time1")

				script.Parent.Text = stat.Value

				stat.Changed:Connect(function()
					script.Parent.Text = stat.Value
				end)
				if stat.Value < besttime.Value then
					local ColorNew = Color3.new(0.333333, 1, 0) --GREEN
					script.Parent.TextColor3 = ColorNew
				end
				if stat.Value > besttime.Value and besttime.Value ~= 0 then
					local ColorNew = Color3.new(1, 0, 0) --RED
					script.Parent.TextColor3 = ColorNew
				end
				-------------------

				EndBrick.Touched:Connect(function(hit)
					local endplayer = game:GetService("Players"):GetPlayerFromCharacter(hit.Parent)
					if endplayer ~= nil and endplayer ==  game:GetService("Players").LocalPlayer then
						go = false
					end
				end)
			until go == false
		end
		wait(0.5)
		db = true
	end
	--Clearing timeran and replacing leveltime
	if go == false then
		local player = script.Parent.Parent.Parent.Parent.Parent
		local leaderstats = player:WaitForChild("leaderstats")
		local stat = leaderstats:WaitForChild("runningtime")
		local leveltime = leaderstats:WaitForChild("time1")
		if stat.Value < leveltime.Value then
			Replace:FireServer(leveltime,stat)
			script.Parent.Parent.BestTimeValue.Text = stat.Value
		elseif leveltime.Value == 0 then
			Replace:FireServer(leveltime,stat)
			script.Parent.Parent.BestTimeValue.Text = stat.Value
		end
	end
end)

Server Script

local remote = game:GetService("ReplicatedStorage")
local remoteEvent = remote:WaitForChild("ShowTime")

remoteEvent.OnServerEvent:Connect(function(player)	
	player.leaderstats.runningtime.Value = player.leaderstats.runningtime.Value + 0.1
end)

Please ask me if you need any more information. Thanks so much!

The answer is yes, anytime anything is calculated on the client rather than server side; it's exploitable. All calculations & hit detections must be done on the server side to avoid exploitation & lag switching & collision latency can still be messed with to achieve impossible/difficult result without actual skill.