I thought I would post here and let you guys know that the feeder pump fix worked for me. I am copying it from my post in the Volkswagen forums, so a few things will sound funny.
I finally got enough money to repair the issues the car has been having.
I reworked the fuel system so that a Carter carburetor pump has taken the place of the Bosch 044. It has an upright configuration that made it hard to retrofit, but I made it work with a very funky fitting that I will get a picture of soon.
Then I cut some lines up and spliced in another Walbro pump near the passenger rear shocktower. It is a smaller Walbro(GSL-393) than the one I had before(GSL-392), but still flows enough fuel at 70 psi to make 300 FWHP. I went with Walbro because I found it for cheap on ebay, I was assured that it was brand new and genuine, and I already had the AN fittings for it. There is an inline 35 micron filter between the two pumps, but other than that it is a direct feed.
Electrically, I wired them up with seperate 4-pin relays. The walbro has a direct fused line from the battery, and grounds to the ground strap on the trans. The Carter accepts power from the main fuseboard in the trunk. I used the fuel pump output on the megasquirt relay board to trigger both relays so that the fuel pumps will turn off with no engine signal (so I have a relay triggering two relays, haha). Additionally, the Carter's power supply is interrupted with a Ford inertia switch. Brian at BoostEngineering.net gave me one free with my EDIS kit. It is mounted in the front apron and will disconnect power from the pump if there is a jolt (from a crash). I have scraped the swaybar several times and am happy to report that it hasn't prematurely cut off yet. It also makes for a really obscure killswitch when the car is parked somewhere.
Other than a leak from one of the fittings that was easily repaired, the startup was perfect. Static fuel pressure is rock solid, with no noises coming from the Walbro. The Carter is a little loud but pretty indistinguishable once the engine's on.
So to all the old heads on here ( Pile, raygreenwood) who kept wagging your fingers, you won. It works. I am a believer. Sorry for doubting the necessity; even now if I could get away without a feeder I would have, but here I am. Best of all, the two small pumps in combination use less peak amps than the big Bosch. Symptoms I had before that some relate to fuel temperature (cavitation, boiling) never occurred. It was 100 degrees out today, and the fuel never hiccupped once. Can't wait to do some real tuning on this thing.
Took mom out to get lunch. I can tell how much I'm going to love this car by how much she hated it.
EDIT: here's a picture of the Carter, with the crazy fitting I made from some NPT tubing and a -12 weld-on bung.
Also, I was playing with the engine when I got home and the fan sucked in a spark plug wire. Woohoo! One step forward and two back. Need to figure out how to make another, and then secure them to the firewall properly. I'm so happy the fuel system works I'm not even that mad.
EDIT # 2:
For anyone that wants a good deal on this pump, here's the link: 75 bucks with free shipping and install kit. When the link goes bad, the seller's name is djd16. http://cgi.ebay.com/ebaymotors/BMW-E30-E12-E21-M10-M20-M30-New-Walbro-GSL393-Fuel-Pump_W0QQitemZ220440180907QQcmdZViewItemQQptZMotors_Car_Truck_Parts_Accessories?hash=item33534238ab&_trksid=p3911.c0.m14&_trkparms=65:12|66:2|39:1|72:1205|240:1318#ht_2877wt_1191