Question about Widescreen & 4/3 useage

[Elandyll]

Hi!

Finally yesterday my setup was completed.
Within the same week I had the pleasure to setup my new TV, a Samsung HL-T5087SA (50" Slim Led projection TV), my new HD DVR from Cox and yesterday the very much awaited PS3.

Now, my question is this. After trying various settings concerning the picture and how to handle TV signals, The "Fit Wide" setting leaves me a bit wanting (as it stretches the 4/3 signals to fit the screen).
I would very much prefer to leave if to "Auto", where the TV detects if the signal is widescreen or 4/3, but I am afraid that repeated use of 4/3 signal on a widescreen TV will result in some sort of "Burn In" or seeing some kind of "edge" wehre the 4/3 "box" is.

Is that a real possibility? Should I use "Wide- Fit " anyway then even if I don't like the deformed and enlarged picture?

Thanks !