Broadcast/professional equipment uses BNC connections for video cabling, to minimise signal degradation from back-reflection caused by impedance mismatch. The X0 team actually modified their PDI Deluxe capture card to swap the RCA with a BNC connector.
Arnie, in those clips you posted, did you crop then add the black bars back in? I'm asking because the black level of the bars is pure black, whereas the black in the actual video is elevated a fair bit higher. There is no clipping of the whites - in fact, I would recommend increasing the contrast.