It's not all that.
The mighty 525iT had about 10% displaying on the "multi-information display" which makes the radio/CD/on board computer essentially useless.
I read a lot of stuff on the various boards, which mostly makes me appreciate here even more. Eventually I bought a replacement ribbon cable w/ a neat little silicone-faced soldering iron tip on eBay for about $30 shipped.
The M.I.D. pops out w/ a T9 Torx in about a minute, and I had the covers off and the circuit board/ribbon/LCD isolated in about 15 minutes, working carefully. Everything uses that T9.
You snap off 2 long spring clips, peel off the silicone foam pressure strip, and peel the old cable off. The residue is removed the LCD w/ acetone and a q-tip - mind the faces - they're plastic which acetone will etch. The traces that you'll iron the new ribbon down to are plated on the glass strip and are barely visible. The gold contacts on the circuit board get the same treatment, acetone/Q-tip, and a pass with an eraser to shine them.
The soldering iron tip (5mm shank) goes in your iron - 40W minimum. I had to turn a brass adapter sleeve as the bore of my good Weller station iron is about .260". Once it was in and hot...
You carefully - VERY CAREFULLY - align the bazillion microscopic runners on the ribbon with the corresponding runners on the LCD. I was wearing reading glasses and a +2 diopter Opti-Visor and had a high-intensity lamp. I lined up one end perfectly and ironed maybe 1/4" down for 5 seconds. I pulled the other end of the ribbon - it's about 6" wide - to line up wither the other end and tacked it down, then ironed the whole thing carefully.
You repeat the process on the circuit board then apply Kapton tape if you have it, or scotch tape if you don't,on the backside of the LCD and board, then lay the silicone foam pressure strips on, fold the ribbon over and secure with the spring.
Reassembly is a bit fussy getting everything in order, the display spring clips on, and all the small ribbon cable connectors on - but it all goes together. Reinstallation in the car is 5 minutes.
Every pixel works, and the display illuminates crisply and brightly. If I did it again it would take an hour in total, and wasn't difficult - it just requires care and patience and a little mechanical intuition.
BTW - the general concensus on bimmerforums is "Naw dude, that never works. Buy a remanufactured unit from (dude w/ a million eBay auctions) for $200"
