I added these aero mods, skirts and belly pan, changed the oil to 0w20 and aired up the tires to 65 psi, she rolls down the road almost effortlessly now at 55. I think it was mostly the tires were at 50 psi.
Went to junk yard to get a spare tire and wheel, but they closed before I could see if the wheel fits the car
I connected the aux tank to the main fuel line with a check valve (PCV valve) line and filled up both tanks, we'll wee how far she gets down to 1/4 tank.