I think the consensus is, worth it, but not absolutely necessary. A lot of people went without them on the BAT kit. Since the price dropped, I think they've become a bit more popular.

I got them because I wanted the adjustability for stuff like autocross, not because I felt the car would be ruined or out of spec without them.

Function before fashion. '96 Contour SE "Toss the Contour into a corner, and it's as easy to catch as a softball thrown by a preschooler." -Edmunds, 1998