Successful disa repair
I would like to thank the E46 community for their help in diagnosing and providing guidance on replacing the DISA unit on my vehicle. All went very well and car is running much more smoothly now.
A couple of items for the cherries out there (my fellow cherries). I removed and changed out the air filter and the removed and cleaned the MAF during my process. I also removed the next intake piece behind the MAF though this was likely not necessary. If you do remove it, take a look down into the throttle to see if it is clean. Additionally, if you do remove this piece, put a clean rag or plastic over the hole leading to the throttle. You don't want anything getting down in there while you are working on the DISA.
I took the intake piece out before the DISA, which was a major PITA. So another reason to avoid doing that. But if you do take it out for some reason, replace it before you put the new DISA back in. It is a lot lot easier to put that back on and tighten the clams without the DISA being there.
Back to the story. My DISA was fried. I had initially thought about rebuilding it, but after I got a look at it I opted for the replacement. The plastic piece at the base of the flap was completely eaten away and disconnected from the flap. I read in the threads about whether the DISA could disintegrate and fly into the engine. Looking at mine, I believe it could happen.
Some other tidbits. The lower screw of the DISA is in line with another screw of exactly same size. So, me, of course, took out the lower screw, that I believe is a connector for the ICV. So if you have taken out two screws that look exactly alike and are getting resistance from the DISA in trying to take it out, make sure you have taken out the right lower screw. I have read here about a guy complaining about having a hard time taking his DISA out and I suspect this might have been part of the issue--though he may not want to admit it.
When you go to put the DISA back in, I found it helpful to have the back end (the end closest to the cabin) touch the manifold first and then angle it in from there--from back to front.
Only other issue is that it still throws 2973/2974 codes at me, though I guess from reading the forum that is not unusual. Anyone have any ideas on how to get rid of those once and for all? Car runs fine, so I think it is more of a problem with the SES programming then an actual problem with the engine.
Thanks again, between Youtube and this forum this is a repair that anyone can make.