I would think that the chatter you're gonna get with an unsprung 4 puck and lightweight flywheel will pound your fillings out the roof of your mouth. I have the act 6 puck and i get chatter, mind you it's managable...but still.
The 6 puck is labelled as a race only clutch, mind you i'll argue that point simply because it is driveable. I don't even want to know what the 4 puck would be like. Is this a daily driver, if so pop the clutch and get something else. My daily drivers busted so i've been driving my supra everyday for the last 3 weeks and at moments I've thought about ripping the clutch out and tossing it.
Good luck