<E-30> Buying a throttle body???

[Larry Schwarcz <lrs@xxxxxxxxxx>]

While replacing some coolant hoses on my '90 325iC (E-30), the screws 
that hold the throttle body pre-heater to the throttle body broke off 
and won't come out.  It's set up now to just by-pass the pre-heater for
now.  This works fine for now and probably won't be a big issue here in 
the San Jose, CA area.  It's my understanding that this is only needed 
in *really* cold weather.  It seems to be running OK.  

So...

   1)  How cold does it need to get for this to be an issue?  While
       I've never seen it snow here, it can get down to freezing temps
       on rare occasions.

   2)  The best price I could find on a new one is $365.18 from The BMW
       Store in OH.  Any suggestions on other places to try?

   3)  How about a used one?  What parts typically come on a throttle
       body?  If I bought a used one from a junk yard, would I just
       be getting someone's worn out unit?

Trying to rebuild mine is probably not easily possible since it would
probably take more than a day.  This is my only car.  I would be stuck
at home until I got it repaired.

Any thoughts or suggestions are welcome.

          Thanks!
            Larry Schwarcz
            lrs@domain.elided

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