Can you use a cylinder as a car base and add it more things?

I know that a cylinder can be used as a car but... how do you weld things into the cylinder and also how can I add decorations if its a cylinder? :/

Make a bunch of individual welds:

for h,i in pairs (game.Workspace.Car:GetDescendants()) do
	if i.ClassName == "Part" and h.ClassName == "Part" then
		local w = Instance.new("Weld")
		w.Parent = game:GetService("JointsService")
		w.C1 = i.CFrame:toObjectSpace(h.CFrame)
		w.Part0 = i
		w.Part1 = h
	end
end