The paperwork is fairly easy. I would suggest forming a trust or LLC and registering the NFA items to that. It will save you the finger print and law enforcement hassle. It is also the same amount of paperwork to build one as buy one. I am building three and will have about $150 in materials and $600 in stamps. I am at the welding point and just trying to get the tig setup working correctly. If you checkout Silencer Talk
there is a lot of good information on there about the paperwork and building if you choose to go that route. If you want any more detailed info feel free to PM me.