not sure, didnt say if it requires a new belt. if theres not enough adjustment then ill just get a slightly larger belt.
not much info on these but iv found a few people who claim it helps, and this cars always run hot so thought id give it a shot
It does. Its not hard to figure it out though The part numbers indicate the length and the number of teeth.
Also, its to prevent water cavitation as you mentioned - bubbles! But only at high rpm.