Time for a new Transmission

[skinnison]

I posted a couple of weeks ago that I was loosing reverse in my 1995 E320 wagon. Well, it's all but gone. After research I have determined that it is too risky to have the reverse fixed only and not have a complete rebuild. A rebuild is very expensive too, especially seeing as I just had the headgasket done in March! (When it rains it pours). So, my questions are:

Is $1350 a reasonable price for a used transmission with 110,000 miles on it and a 6 month warrenty on parts? (Another $850 for labor).

Is there any value to my transmission after it has been removed or should I just let my mechanic take it? It has 196,000 miles on it and obviously in need of a rebuild.

Any words of advice in general?

I do trust this mechanic. The owner of the shop is a Mercedes master mechanic and the work they have done to date seems very good.

Thanks