what the hell is this?!
 

I have a 88 300zx non-turbo and I removed the downpipe for other repairs. I needed to replace a section of pipe due to rust and it had a little tube that went where the pipe got replaced. I have yet to make accommodations to fit that tube in hopes that I can remove what ever this is all together.

For those that aren't familiar. It has a tube that goes to exhaust, a tube that goes to intake, a vacuum line that goes right after throttle body, and a vacuum line that goes to some sort of vacuum solenoid.

What is this called? what does it do? do i need it?

http://imageshack.us/a/img21/8338/photo1jzj.jpg
http://imageshack.us/a/img24/5022/photo2icl.jpg
This is where it goes and the solenoids it connects to. It mounts right under where I have the vacuum line spooled up.
http://imageshack.us/a/img19/4762/photo3zr.jpg

EGR.

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Bzzt!

Aiv.

Yes AIV it adds air into the exhaust stream to help burn some of those nasty exhaust particles, and no you dont need it unless it wont pass e-test then it is possible that the AIV could solve your problem