Yes DB, the GS or Grand Sport option was another admirable product-planning highlight under Bill Bourke and your comparison with a four-door Mustang is valid. When you look at the list of GS options for the XW Falcon, the choices fill a full page covering engines/transmissions, power-assist, luxury, exterior, wheels/tyres and more. It would have been so easy for a Falcon 500 buyer to get so carried away ticking those boxes that they ended up with a Fairmont equivalent or better! The GS option was eventually offered on utes too, the XA being the first recipient. There must have been some very desirable GS utes around in those days.