3.23 is the "compromise" rear. Even better with an RB. But if you have the cash for 2 chunks, God bless you! Most of us would like to have a selection of rears on the shelf.
IDK it's not that much picking up used parts here and there... my current chunk isn't great anyway it's a 741 case although it does have factory clutch-type SG. I just need a 742 or 489 case then put new 4.10 ring & pinion and maybe swap over the SG with a rebuild kit.
The annoying part is how the ring and pinions don't swap between cases which I suppose would defeat the purpose but still...