The coroplast started sagging in the middle under the engine, I ran over a big stick that flew out of a trailer. I could have fixed it but its time to do it better. Road noise has increased without the bellypan. Coroplast is fine for the middle section I think. Polymetal looks very useful, I will look for it locally. A permanent solution with easy engine access would be really nice.
Heres how the splash guards were mounted on this other civic:
A difusser
IS needed and added to the list!
Thanks for the advice freebeard!