so it's time for a new clutch, and I need to know some things before I buy one. I was wondering how much power increase I could get from using a exedy stage 1 pack. and 2nd, does the disk diameter make any difference?

 

your clutch in no way effects power

 

No performance gains from clutch if your still running a stock motor or slightly modified get a sage 1 great for a daily driver still prety smooth shift but noticibly more bite to the clutch. Deff a stage one nothing over that its over kill and pointless