Richard, I have been through all of this already. I have the Holman Moody print for the airhorns, and they were made out of Lexan. I already have made the molds to produce the airhorns, so maybe I can help you out.
I know that you were considering a skid plate to protect the bellhousing on your car. Were you able to fabricate one? I am considering that or if it's possible, adjusting the suspension to gain some ground clearance. I went to the 17" wheels and lost an inch. I just can't bare to bottom out again.