Good stuff Dave,
A bit more information on it from my research:
1. Lowering springs on the older models affected suspension geometry requiring the roll center kit. It will need to be confirmed if this is required for the new models.
2. Exhausts for the new models are still coming, so for the moment there are no 'cheap' options. So be prepared for a ass raping of a price.
3. Stock
ECU re-tuning options are the best bang for buck. Alternatevly try Motec or Autronics.
4. The best bang for buck modification would be sway bars in my opinion. Stock ride height is good (no crab crawling around shopping centers) and with sways you get decent handling too.