for a 92-95 civic SI, Suspension Tecniques offers 2 different front sway bars:

a) front sway bar for civic with stock front sway bar (1 inch diamter)
b) front sway bar for civic without stock front sway bar (3/4 diameter)

Why is it that these are different widths? The rear sway bar they offer is 3/4 either way you go about it.

 

Maybe the Si has extra chasis rigidity?

 

the only thing different, to my knowledge, would be the Lower control arms?

 

If you have an SI then you want the kit with the 1"bar. They have it listed as 2 kits for all 92-95 civics, ones with a factory front bar, and ones wihout. The kit without the factory front bar is a smaller diamerter because it utilizes a different type of endlink but if you car already has a factory bar then the kit uses your stock endlink mounts. hope that helps.