They are two different things here. BG 109 is a flush that attacks the pressurized areas like the ring packs VVT screens and what not. This is a quick one time thing.
BG MOA is like STP, SLOB, etc on steroids.
Auto-Rx is a slow progressing engine cleaner.
I have used the BG stuff and it works. Will not degunk the whole engine however. If you have Carboned up'd rings though it is fantastic. If you want to desludge a motor not a bad start but Auto-Rx would be a great to finish the work safely.
Don't use the MOA or the "compression restorer".
MOA seems to make sludge form faster (at least in the turbocharged engines I was told to put it in) and and compression restorer is so thick that the instructions from the distributor were as follows: "Run hot water over it to thin it out or else it won't come out of the can, or keep a few sitting in the sun before you use it so it stays hot and liquid".
I have used their synthetic ATF, it seems to be compatible with the Volvo 5-speed (JWS3309 spec) but I would never run it in my transmission.
You are correct on the BG trans flush oil being used on a lot of Volvo's. I have been to two independants in the Detroit area for various things (try to do most of my own work though) and they both market that fluid.
I just drain and fill with Mobil 3309 in my S60.
FWIW: I had oil consumption issues with the S70T5 I have and Auto-RX has reduced the consumption to zero since I did the treatment in Jan 09. I use Amsoil AFT in my S70.