The inverter for the indiglo back-lighting resides in the small cluster. So It's best to install that as well. This being said, the oil gauges will not function because the SVT harness is different from the ZX3. So if you want you can always hide the small cluster behind the dash.
@sailor- is this specific to svt clusters being used in normal zx3?
My lights work but are dim. Also the dial next to lights control switch doesn't do a damn thing which I assumed it would allow for brightening the lights or dimming them.