Is it possible to get A and C pillar airbag modules from a salvaged 2001 A4 that had it and just plug it into mine (99.5) Or are there other sensors involved in this.?

 

Japanese cars I've owned in the past have required preventative service to the airbag modules at ten year intervals. I'm not sure if this is the case with Audi - but you should look into it before spending cash on something that will need to be serviced in less than a year.