I've had this pop/click sound when the engine is lugged down a bit harder when I start in 1st gear from a stop. I can also sometimes get it if I change to second gear and floor it. I'm thinking it's a high torque related sound. I got a video of the engine bay while revving the engine and pulling up partially on the clutch in 1st gear. Does this seem like too much motor movement? I'm thinking I'll want to replace the motor mounts if so. Thanks!

 

Yeah, that is way too much motor movement. Check the mounts. I can clearly see the passenger side engine mount flexing in the video.

Also I don't know if it's the microphone quality but your engine seems to be running a bit rough. Is it cold outside?