I finally did it today...
Thx to silver for reminding me time & again!

The workshop (bridgestone) found the culprit! A tiny nail embedded on the tire, patch it up for me for 5 bucks, very nice job!
While waiting, I asked them how much for new set of tires & servicing
They quote me $108 ea for new bridgestone - Turana (wheel alignment & balancing + include free nitrogen top up for life)
$108 for servicing.
Is the price fair or I should cont looking around?