$532!?!?!  This is a $40 part at Napa.  It screws in just like a spark plug
does.  You will be removing the intake plenum but it's just a plastic piece
for the air to go through on it's way to the motor.  There are no gears or
oil there or anything like that.  You will disengage the intake components
on the front of the plenum and then start to unscrew the 8 or 10 bolts
holding it on.  There is a braided fuel line goping into it which you will
not need to disconnect.  Once loose just lift the manifold up and put it to
the side.  The oil pressure sender is on top of the motor towards the back.
If I rememeber right you will need a deep well socket to get at it.  There
is enough room there for a regular wrench-- you won't need any special
tools.  Also, behind the plenum is  a plastic air/vacuum line which you will
need to disengage in order to move the manifold out of the way.  If you go
real slow, it can't take more than 45 minutes to get to this. (15 if you gop
fast and have done it before) You will have it re-assmebled in 20 minutes.
I use a 14 volt cordless drill to remove the long screws.  Save yourself
some back pain from leaning over the motor for too long.

I would do the job for $200 and feel like I got over on somebody.  Five
hundred is way too much.

-Stan
2000 C5 Coupe
1999 Blown C5 Vert