Help w/4000S electric window lift(s)

[marty@globes.com (Marty Udisches)]

Hello all!

As a recently subscribed member of the list, let me first say what
a great list this, and what a wealth of info is available.  Of the
several other car-related lists I'm on, this has by far the best
body of information...

Anyway, one thing I wasn't able to find in any of the archives is
information on the electric window lifts; specifically for my application,
an '85 4kS.  The driver's window lift died amid horrible crunching sounds
recently.  Upon removing the door panel, I saw that the cable that
actually moves the window had broken, as had part of the plastic
body of the regulator/motor unit.  I removed it from the door to 
attempt repairs, all to no avail; 3 of the screws holding the two
halves of the unit together wouldn't budge.  Liberal applications of
Liquid Wrench over several days did no good, nor did unfortunately
liberal applications of heat from a torch...

My questions:
Is a brand new regulator/motor assembly my only choice?

If not, is there a likely source to find this used?  I've tried
the place in Rancho Cordova, CA, and will try others from the
vendor list, but are there used parts places that are more likely
to have this than others??  There are lots to call :-).

The new unit retails for ~$380 if memory serves; what would be the
best source for the part new?
 
My passenger window quit working this summer, and the rears have
never worked since I bought the car used a year ago.  I like working
windows; any comments on the likelihood of swapping in manual window
lifts?  The Bentley manual seems quite sparse regarding info on the
window lifts...

Thanks for any help; surely I'm not the *only* 4k owner who's had this
happen...  Right :-)??

Marty
marty@globes.com