Not a bad price for a car with 12k.
If it is the color you want, offer a little less and see if you can deal. If you are in the north, fall is coming and the dealer will certainly deal on a "summer" car.
If I didn t have one I would have likely taken it at that price, 12k is pretty desireable.

2. Less is usually better just because of wear & tear, and maintainence is always an unkown.

3. Toss up - there are limited mods for the SRT, so there really are only a couple of real options. I prefer original so I can mod and I get to keep the original parts.

4. Seat heaters, I/C pump, tires, leaky trans, curb rash, RCM, then general condition and service records.
All are pretty easy fixes if needed.