Just as a general reference for anyone interested in G4 towers: http://www.outofspec.com/frankenmac/wire.shtml

Also, perhaps you want to toss in a PATA or SATA card to regain ports lost?

As far as removing the connector some would snip, some would pull the black plastic off and desolder the individual pins, some would heatgun the whole thing. It depends what tools&experience you have and what you feel comfortable with.