Air Bags for 2001 LXi

[Urnie-Medie]

Hopefully someone can help. I need to replace some of the air bags on my 2001 LXi. Could someone please give me some suggestions:
1- should I go ahead and replace all - I believe there are 10
2- how difficult is it to replace the air bags
3-the one that has a hole in it is on the tag axel - I have been told that is
probably the easiest to replace.
4- Where can I find the part numbers of the air bags
5- Where is the best place to purchase them

Thanks

Urnie