ETA: Looks like an AK-103 is the obvious winner.
I recently came into a 7.62x39 unconverted Saiga through a local trade, and now I'm faced with some options:
1) Convert it to a full size AK-103 with correct 5.5mm side folding stock
2) Convert it to an AKSU (in 7.62x39) with the correct 5.5mm folding stock, correct length barrel, and permanently attached PBS-4 type faux suppressor to make it legal length
3) Same as option 2, but keep the barrel long with no faux suppressor
Now, I already have an AK-103, AK-104, and 7.62 AKSU in my collection, so think of it as what would YOU prefer if I were to offer it to you in a future trade or sale (it's not for trade or sale at this time, btw). SBR is not an option at this point since I already have an SBR'd version and don't want or need two of them.