Would be a viable solution if your using the RCA's from the HU.
The loom just requires the top and corresponding bottom wire to be connected together, counting back once you figure out which pin goes to which. If you can solder then your 3/4 of the way there. I used the wiring off the mazda3forum, and noted that there is a pin which does nothing on the incoming loom, so with the PAC loom you just need to count 1 more across (sounds confusing but makes sense when you look at socket).
So not really plug and play, but not a great deal of effort if you can solder. I'd recommend not doing the dodgy and twisting and taping the wires.