From where you are now:
These are the 3 big things I would go after. Camber plates are critical, if you're serious about handling, FWD strut cars need serious negative camber up front. The LSD is not specific to handling, but it will help you get more power to the ground sooner, which is always a good thing. Bushings will help tie everything together and tighten up the whole package. Front LCA bushings are the biggest help here, the improve the feel on turn in.
Even though I don't know your spring rates, the eibach bars are probably more than stiff enough. The adjustable endlinks are a nice addition, but the best way IMO to use them is to eliminate any binding or preload in the system. Your sway bars should move freely with no bind, allowing them to work at the predicted stiffness, and improving tuning the handling of the car.
Parking Lot Hero
2008 WRX daily driver
2003 ZX3 23D Autox Car 42 FSP
"Hella Functional - Raced, Not Hard Parked"