How much performance, how many dollars?
 

Hi folks,
Just recently got a new-to-me 2009 Crown Vic from the sheriff's department auction. 109,000 miles on it, some interior stuff missing but hey, it was $1,000
I'm looking to increase mid-range power, say from idle on up to 4,000 RPM. The "gotcha" is that I live in California, so:
*head swaps must be able to pass at least a casual visual inspection when I smog the car / not get noticed
*engine swaps / internal mods, ditto
*bolt-ons must carry a CARB number
*engine swaps must come from 09 or newer model year cars (no truck motors) if they are visually any different.

So, that in mind, what can be done with a Vic and for how much money?
As I type this all out, I'm thinking "gears" is all I can do short of trying a sneaky 5.4 swap.