me7.5/7.1/7.1.1 all share an ecu connector, however the large plug (the one you'll use for bench flashing) has a different key. You can modify the plug (super easy) or snap the key off the ecu. (picture shown)
s4's/2000MY a6's/non immobilizer equipped me7.5 vehicles all use the bottom plug. Newer immo equipped cars use the top style. Plug is the same, but note the small key inside.
In short, you can use the plug with slight modifications to make it fit the style key you have in your ecu.