Your write up was great. My car was doing this weird boost osilation and on logs the throttle was going up and down kinda like a heartbeat. I'm running MHD map 2+ for E30 but when I flashed back to stock it wasn't as noticable but the logs still showed it, just not as extreem. I did have the squeal from the rear main seal but I didn't know what it was till I stumbled on this post. Got my new valve cover on a few hours ago and she's back. Boost is nice and steady and hitting 20 psi again. Thanks for posting your findings.
