Mike Trent in Houston is a great guy, he has done 3 MG and 4 Silencer as well as 1 SBS X-fers for me, all went off without a hitch except for the the 1st MG..which was a paperwork SNAFU. He charges 50-100 bucks per NFA X-fer depending on the item.
His contact info is:
1425 N Durham Dr.
Houston, Tx 77008
[email protected]