Since I have the tpi plenum off, is there anything else I should replace? I got all the gaskets for around the plenum. Should I bother replacing the EGR (I think that's what that big round thing under the plenum is)?

 

So it is; you could at least pull it and clean it; use some anti-sieze on the bolts upon replacement.

Now would be a good time to move the MAT sensor into the air filter box. I got a 3/8" pipe thread plumbing fitting with a "vacuum" extension that I capped with a vacuum nipple.

 

if you have a MAF car, there is no reason to justify moving the MAT. do a search, the prom guys have proved this.

 

Yeah, don't bother moving the MAT. Clean out the plenum real well, they get some nasty build up. If you own a dremal you could knock out the EGR walls and pick up a couple horses.