There is a reason you think these shocks are so great, you have no clue.
The fact you think a shock is just gas, springs, and straight metal is funny.
You do know shocks have valves right, also good shocks have oil in them. The valves and oil play a huge role in how the shock works.

But instead of spending your money on gas, oil, springs, valves, some metal, you rather spend more on just straight metal and some welding.

FFS you are stupid.