I have to disagree with this reasoning...
Adjustable UCA's give you more caster - caster equals more straight line stability especially at high speeds. so anyone going above 45 mph will benefit from the added caster of an adjustable UCA, or as much positive caster you can get out of a stock UCA - I got 4.5 degrees out of my stockers and thats about as far as you can go.
An adjustable UCA can give you as much as 7 degrees positive caster so when you have skinney's up front and meats out back the car will want to go straight and not wander. those big and little combo's of tires are harder to control then rubber bands and you could use all the help you can get at the drag strip!
