After you mentioned it, I asked around about the YA one. Turns out it was never kitted, the only one I saw was the prototype flown by Bob Fiorenze. So, it's AD or no stealth at all!
Besides, Bob Parks has done a lot of the thinking for me already, as he has one of the kits.
If you want to do another pipe, I will finance it, but what will it cost me?
I could live with nine pounds of thrust...but ten would be much better!