Ed, there are two different types of oxygen sensor.  A single wire and a
three wire.  Your van needs a three wire (which is more expensive).  You also
have the choice of splicing in your old wires (I have these for $50 each) or
one with the original connectors on it that you just plug in (these are $120
each).  It basically comes down to how confident you are in your splicing
abilities.  Alot of people don't want to mess with splicing and just go with
the OE one to avoid any problems that an improper splice can cause.  I would
also advise if you are doing this yourself that you get a pipe wrench and a
can of some type of penetrant.  Soak the old oxygen sensor in the penetrant
for an hour before you try to remove it.  Then use the pipe wrench to take it
out (I haven't found anything that works better because these things are in
there).  The new! one will have anti-sieze on the threads when you get it.  I
hope this helps.

Thanks,
Ken Wilford
Van-Again
John 3:16
http://www.vanagain.com
Office: (856)-765-1583
Fax: (856)-327-2242