What is it?

[Quincy56]

This rubber bit below the intake manifold doesn't look so good. Ignore the duct tape on the vacuum hose next to it, I've got that on order. :)

This shot is from the drivers side, from more far away.
http://home.comcast.net/~adamsjohn/318i/WhatIsIt3.jpg

This is a close up shot from the same angle
http://home.comcast.net/~adamsjohn/318i/WhatIsIt2.jpg

This shot is of the end from the front of the car, it seems that should connect to something.
http://home.comcast.net/~adamsjohn/318i/WhatIsIt1.jpg

[tjts1]

Have fun
http://www.m42club.com/forums/showthread.php?t=2742

[Wizard]

Honestly I would just follow tjts1 advice and rip everything out per the thread. Did mine a couple weeks ago and car runs 100% better.
From the looks of the pics, there is a lot of nasty grime and some rust.

[Quincy56]

Thanks guys.

What sorts of parts should I have on hand? I would like to start and finish the job in a day or two, and don't want to have to have the car sitting waiting for more bits to arrive.

I assume I need some new hoses (heater and vacuum), intake manifold gasket. Anything else?