From my limited ownership and forum knowledge It appears you can possibly eek out a few horsepower from exhaust, intake, and NA chip, but I haven't seen much data that suggests (without an additional custom tune) you can get more than 10-15 HP from these plug and play mods.
it seems to me that if you really want a big jump, you have to go Forced Induction starting around 2.5k for a used older gen SC kit (kit only) or up to the 5kish for the latest brand new kit. Install is another issue entirely.
anywhere up to 1.5k I have been quoted for the install cost.
I would look for the forum thread about cost effective HP gains.
In my opinion if your really looking to for some gain and want to pinch the penny i would install pipper stage 3 or 2 cams full exhaust and a thicker head gasket to set your self up for a turbo once the 220hp honey moon is over. But your going to need a tune and that's were the piggy bank starts to cry.
In my experience i can tell you to bolt on stuff all day but these cars do not benefit much from the upgrade till they are retuned. Consider lowering your dual cam engagement RPM.
If you have no intentions of going past the 220 buy a used older model SC most guys pair them with there pretuned ECU.