With the BATFE regs on 'pistol braces' being what they are now, I'd be tempted to go that route. Of course, you never know when those unelected bureaucrats will change their minds yet again.
This uses the original standard Colt 9mm magazines, which I prefer over those designs that use Glock mags. But both are good choices. I've run all sorts of 9mm loads through this gun without any problems at all.
Even me being an LEO, it would be near impossible for me to get an SBR. So I’m going to go the pistol route while I still can. Obviously it’s almost the same set-up. Yours is a nice one.