I wasn't thinking of replacing the barrel on the carbine but rather just having it chopped and threaded by ADCO. I'm actually having trouble finding the 922r stock/kit for the pistol version. I suppose the only added benefit with SBRing the carbine is that the suppressor would sit under the handguard but that would mean I would always have to run it with a suppressor.
I read somewhere that someone is working on a barrel nut wrench for the carbine, so a barrel swap/chop+rethread shouldn't be too difficult.
I have the carbine, as I didn't want to hassle with 922r or pay an extra 200+ for the stock. The handguard is a nice bonus too, and if you put a flash can on the shortened barrel, you could probably still shoot unsuppressed if you ever wanted to.