> I guess what I'm really asking is, is it possible to get a bit perfect and roms split
> correctly from a cart dumper.
Bit-perfect? Sure, why wouldn't they be?
As for split files or merged - in the context of individual files for individual chips or one large blob, not in the traditional MAME ROM torrent terminology sense - it doesn't matter.
I don't know if byuu does split ROMs or not. I seem to recall that that was a large point of contention between him and the team in the past.
I think the argument of split versus merged in the context of what byuu is doing is silly anyway. He takes high-DPI lossless scans of everything, including the PCB. He also creates a full map of the cartridge's entire address range. Again I don't know if he uses split or merged chip data, but from the info that he archives, a sufficiently dedicated person would be able to split out the chip data accurately.
He knows what he's doing.