Modifing Brackets for Headers?

[THE "10" SILVERADO]

I remember reading somewhere on here that if you are going to install headers on a late model truck engine you would have to modify your A/C (and if I remember power steering) brackets because they are bolted onto the stock manifolds. Well for Christmas I might gift my self to a new exhaust system and I was wondering if this is true for (1) and for (2) what are all of the parts I need to buy (like new brackets) and (3) if I were to get new brackets would these be suitable to any type of headers I could buy?

Thanks In Advance
Michael