So the exhaust thing is normal
and the hum/knocking noise is coming from the silver thing, like i can put my ear up to it and hear it. so the actual VANOS chains and stuff isnt on the silver thing, cause if so i dont see what the silver thing would be doing to make a noise
and yeah it was a puff(ish)(more like a puff that went on for a sec then went away) the more it was driven the less of a puff I saw of white/greyish (but more lightly colored grey) smoke, DEF not black and DEF not blue, smelt like Hot exhaust when he floored it, so i guess thats normal? i guess the water dripping out the back gives it away, but would the exhaust get hot enough that fast to do that? im guessing?