i think need to fill in passport detail coz im going to indonesia

hi...
this is actually my first time booking thru internet for airasia
and stupid me...i'm forget to add pre-book supersize baggage
which is important for me!!you know lah...want to shopping "sakan"
sure will bring a lot of thing when came back
one question...
can i still manage to get a pre-book fees for excess baggage@supersize baggage after i already make a payment@booking???...
because what i see in their website....
the different fees from pre-book and check-in counter is quiet huge...

I have an economy ticket that needs to change the passenger's name.
So I have to visit the service counter at KL Sentral and make the changes there? Any other ways? And I can go to change the name on my own or the new passenger have to go in person as well?
Please help。

Do I need to update my passenger details since I only bought the tickets using their DOB.

I'm going Singapore next week via AA. So do I need to update the passenger details? Or I can just check in accordingly?

tomorrow got free flight!!! heheheheee
btw, forgot l how to cancel the insurance and pick a seat option...
anyone mind to share? don't want to get cheated again, hehehee...
tqtqtq