All good questions
I own the manuals as it is another fact based reference point to use. The Bentley manual is just an manual in book form. Locked in time when printed. It will never get better over time like this forum which has many years of real DIY efforts and postings, most are greater than the BMW service manuals as we post the REAL TIPS and TRICKS on any given project. Plus many posters are really interesting in helping others gain and share a knowledge base that can help over come the dreaded "WTF!!!" when problem A appears not to have a simple solution. A good example is the loose positive wiring at an alternator/starter that shorts, fits and engine no starts and or dies at speed issues. No manual will show that info. It can only be found in real world problem solving.

The problems with forums is that it is open sourced, very little structure, and lots of misinformation gets posted by those with little auto knowledge. In this forum thank God, there are many who share their combined knowledge and can be counted on to offer a tip or two.
Bottom line: Print off what you know to be true (Specs, torque settings, etc) and save a few bucks. Or buy the manual and write in the updates!

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2005 X5 4.8IS
The Blue ones are always FASTER....

Current Garage:
2005 X5 4.8is
2002 M5 TiSilver
2003 525iT
1998 528i
Former Garage Stable Highlights
2004 325XiT Sport
1973 De Tomaso Pantera, L Model
1970 Dodge Challenger T/A 4 sp Alpine White
1970 Dodge Challenger T/A 4 sp GoManGo Green
1971 Dart Sport, “Dart Light” package
1969 Road Runner 383
1968 Ply Barracuda 340S FB Sea-foam Green