The Tein are very good, and though not cheap, the best route to go down to lower your IS.
The EDFC is not needed, but is lovely little toy. But changing the damper setting while driving not very often needed! Though great for occasional track use etc. Personally, and I'm sure others would agree, I'd rather spend the money on some uprated ARBs (Anti Roll Bars) as this will improve the handling no end, and can be easily fitted at the same time.
Ive priced the springs and coilovers for 540 euro for the set, is that a good price?? how much is it for the ARB's? any recommended make?