ive lost count of the amount of FAI chains ive fitted no reported problem from my end
if your on a budget get the fai
i also say if you have the money get the gm main chain as its the most important and then the fai balancer chain as its just for the water pump and bal shafts so not so critical and only £67
the bolt stretching is down to oil in the thread as there's no stop at the bottom of the hole
with the oil they won't ever lock at 10nm i have recreated this issue even with gm bolts in a block with oil in the threads i have here as i wanted to see the out come