Yeah, i've seen those but i prefer soldering my own as you are assured of a solid, reliable connection.
Im curious why you went to the trouble of depinning the standard plug in the first place, every time i've installed a stereo i just go in and hack the plug off with a few cms of wire still attached, replug it into the stock stereo and put the whole thing in a safe place.
That way if i ever have to revert to the original system, say if i was selling the car, its a simple matter of stripping back the wires and either using a set of crimp connectors or just twisting the wires together again (cos who cares, i'd be selling the car anyway).