Change Tycoon Drop Shape? (Mesh/Object)

Hi, I am very new to scripting, but I really want to get good at it. I have been following a tutorial on Youtube for making a simple Tycoon. But I have come to the point where I want to change the drop shape from a cube to a Potato. Here is the script running at the moment, I have looked at other scripts for dropping swords and hats, but I can get it to work, please help. It would be great if you could take the script add add on the part with the Potato. Also, heres the potato ID: http://www.roblox.com/asset/?id=81684482 Thanks in advanced.

wait(2)
workspace:WaitForChild("PartStorage")

while true do
	wait(4.5) -- How long in between drops
	local part = Instance.new("Part",workspace.PartStorage)
	part.BrickColor=script.Parent.Parent.Parent.DropColor.Value
	part.Material=script.Parent.Parent.Parent.MaterialValue.Value
	local cash = Instance.new("IntValue",part)
	cash.Name = "Cash"
	cash.Value = 100 -- How much the drops are worth
	part.CFrame = script.Parent.Drop.CFrame - Vector3.new(0,1.6,0)
	part.FormFactor = "Custom"
	part.Size=Vector3.new(1.4, 1.4, 1.4) -- Size of the drops
	part.TopSurface = "Smooth"
	part.BottomSurface = "Smooth"
	game.Debris:AddItem(part,20) -- How long until the drops expire
	
end

Right, so I did that, but, it still doesn't work.

wait(2)
workspace:WaitForChild("PartStorage")


deb = true 
script.Parent.Clicker.ClickDetector.MouseClick:connect(function(wat)
	if deb == true then
		deb = false
		    local part = Instance.new("Part",workspace.PartStorage)
            part.BrickColor=script.Parent.Parent.Parent.DropColor.Value
            part.Material=script.Parent.Parent.Parent.MaterialValue.Value
			local mesh = Instance.new("SpecialMesh")
			mesh.Parent = part
			mesh.MeshType = "FileMesh"
			mesh.MeshId = "rbxassetid://81684482"
			mesh.TexureId = "rbxassetid://81684482"
			local cash = Instance.new("IntValue",part)
			cash.Name = "Cash"
			cash.Value = 1 -- How much the drops are worth
			part.CFrame = script.Parent.Drop.CFrame - Vector3.new(0,1.3,0)
			part.FormFactor = "Custom"
			part.Size=Vector3.new(1, 1, 1) -- Size of the drops
			part.TopSurface = "Smooth"
			part.BottomSurface = "Smooth"
			game.Debris:AddItem(part,20) -- How long until the drops expire
			wait(.15)
			deb = true
	end
end)