I replaced all but two fuel lines with new Viton lines and at the same time replaced all of the o-rings with Viton o-rings. I had the injectors sonically cleaned and recalibrated to 5 bar higher than stock, per Elsbett instructions.
Since I have meticulously done all of the work slowly over a 3 month time-frame, I have carefully watched the results of each change. I have never had any fuel leaks at any time anywhere. The entire car is dry as sand, front to rear.
I am just searching for something that I might have missed that would so drastically decrease the mileage which seems to be still dropping. Drove 80 miles today in gridlock freeway to high speed to in-town and car not only runs flawlessly, it absolutely screams with performance and outruns most anything off of the line. Just totally high fuel consumption.
My next step would be to return the fuel routing to stock and see if the mileage returns.