> Is there something wrong with Cowering's original GoodTools (are cowering's
> tools more trustworthy/ dependable?), or maybe in the conversion to dat files?


The ROMs have to be headerless to match the checksum. Goodtools skip possible headerinformation, cmpro doesn't.
Both files are rather easy to fix. Get a hexeditor and remove some bytes at the beginning...don't remember the exact number...but the files are this size afterwards:

1.161.344 music demo (2002) (scatologic).jag
2.097.152 brutal sports football (1994) (telegames).jag

Roman Scherzer
ClrMamePro