Not to evade your question but, if you are adding rear speakers to the Wing: http://www.electricalconnection.com/audio/speaker_gl1800.htm
Also, no all front speakers are not the same. In 2006 the premium audio Wing became the base model and those front speaker systems are different than the 01 to 05 models
I have an 05 with out back speakers and would like to up grade front and add rear. Has anyone done this and which brand should I buy,,, in your opinion. I haven't heard the 06 system compared to 05 is there that much difference.