B12 - I had these before coilovers, Was a waste of money. The B12 kit slammed the car as the front springs kept on sagging. Even if the front height was ok, the spring rates are pretty much stock so still heaps of body roll if you tend to push your car. The shocks are valved for stiff compression to give the illusion of sportiness. I ended up going to coilovers. ST X, KW V1 or Bilstein B14 would be a better option. I ended up going for KW V2, but now going to upgrade again with custom spring rates.
Subframe bushings - Install KDT917 and not the inserts. Do the job once and properly the inserts tend to go soft after a year or so.
http://www.1addicts.com/forums/showthread.php?t=1158856
Front sway - These reduce the amount of body roll and quicken up the weight transfer. This gives you the illusion the car has better handling but does not mean your car has any more grip. Also if you throw a E93 front sway bar on the soft B12 kit the front ride comfort will be pretty bad on uneven surfaces as the bar is too stiff in relation to the front springs.