[mwebb]

lowering the rear of the car did help one metro owner
who made a video and tested his car on a highway , one time with his regular tires and one time with two smaller spare doughnut type tires
he surmised the improvement was due to decreased rolling resistance of the little doughnut spares
but
METRO MPG inadvertantly proved that guess to be false with his test on rolling distance es with various tires including doughnut spares

yet there was a measured difference / improvement in FE with the rear of the car slightly lowered with the smaller OD tires

i swag it was due to an aerodynamic improvement , a smaller signature to the wind

a wee bit of searching on this forum should provide those posts