long story short, took shaft off today, joint has no play, which is good, but I see rust all over the shaft and near the yoke, so its just going to die at some point.

one more thing I noticed is that, whoever removed the shaft before me, never bothered to mark anything or try to put the spacer/balancer back onto the shaft like the FSM say, but I did a search and it seems that most people just put it back on without any issues. so I don't worry too much about that.

so now, Im ready to buy a new shaft, options will be either OE, mazdatrix's steel or Aluminum shaft, or powertrain's shaft.

Im just wondering if anybody ever tried to use powertrain's brand shaft. they said its "dynamically balanced" so it should be good ?

just in case its out of balance, anybody tried to balance the shaft again after you "lost" the original alignment (the mark on the rear differential)