here is how my wife and i justified $5000 extra on a (entry) luxury vehicle. compared to our 2nd choice we got:
more safety features (i.e. side, curtain airbags, traction and stability control)
more power (65 hp more, 30 lb ft more)
more power features and memory settings (tilt and telescoping steering section)
better general reliability (either first or second on consumer reports)
better dealer service (rated higher than other luxury dealers)
others (rear tint, bigger wheels, adjustable hid, dual chrome and tuned exhaust, better leather,...)
lastly, the price fell within our budget
