The rotary knob to the left of the key is the idle adjust. You can set your idle a little high when starting and then lower it as the vehicle warms up. Mine is broken, so I use the "gas" pedal to give it a little extra fuel when first starting up. Not ideal, but it works.

Your idle didn't sound too bad. Mine is also a bit rough and noisy like that.

Regarding the very low power, perhaps there is a blockage of either fuel or air. Since you replaced filters and fuel lines, it hopefully isn't the fuel (it might indicate a bad injection pump). Check the fuel tank ventilation and make sure that it isn't blocked (that would restrict fuel from leaving the tank). Also, check your air filter to make sure you didn't add too much oil. Did you clean the filter or just change the air filter oil? Maybe the filter itself is blocked with something, which would limit air flow. You could remove the the air filter system from the intake manifold (in a clean environment) to eliminate any possibility of the air filter being the problem.