Value vs asking price vs selling price

Okay, here's the info. I've done as objective a job I can with Vref,
scouted through Trade A Plane, poked around here and there on the Internet
and come up with a value of $45,000 to $49,000. Let's
split the difference and call it $47,000.
If it makes any difference, the airplane is an older model C-172 with a
180hp conversion and a constant speed prop. The avionics stack is
antiquated, but works fine. Whenever the airplane is at home, it is kept
hangared, it has been well maintained all its life, and has a fresh annual.
All the other stuff [TTAF, TBO, PTBO, exterior, interior] were all used in
Vref and other references, so we don't need to niggle with those. In short,
it is a good looking, servicable airplane.
Now it's your turn. What do you think the asking price should be? And on
the other side, how much do you think the airplane should really sell for?