What I like with the plastic shock towers is the amazing flex. I am not to found of using aluminium at stress areas at all. I have considered to make my own shock tower in Kevlar, or perhaps even better glass fiber (as it flexes a bit more & would be very cheap to make in larger numbers as I plan to break a few..).
Here is a video of the first bench test I did this wednesday evening.
[YOUTUBE]http://www.youtube.com/watch?v=6TZIFV_kQTU[/YOUTUBE]
And the direct link if the video does not work
http://www.youtube.com/watch?v=6TZIFV_kQTU