Hi,
I just found this:
http://www.directcircuit.com/products/Porsche-Audio-Speaker-Upgrade-Kit.html
Someone on RennTech used to make something similar that allowed you to replace the dash speakers without detroying the original speaker or doing any modification. This seems similar.
I am not sure what to make of it using zip-ties and having to cut it yourself, but it seems to be the only thing currently available to replace the dash speakers without modifying anything.
What do you all think?