Without question create a "Living Revocable Trust" to purchase any NFA items through.
There is tons of reading about how these work, and how they are set up on the Internet. You can do it (create the trust) yourself, and safe about $300-$500 lawyers fees to have them do it for you.
Seperate $200 tax stamps are needed for each and every NFA item you acquire.
So your SBR would need a stamp and then if you wanted to get a suppressor for it, it would require another tax stamp.
If you want more info or have a lawyer create the LRT look at guntrustlawyer.com
NRA & NAHC Life Member