IMO, this two book E39 1997-2002 Service Manual well worth the money for any M5 owner. The engine service details are kinda marginal anyway, so the fact that they do not cover the 5L is immaterial. How many folks are going to change M5 piston rings?? The book does not cover 2003 E39, but I am not sure what differences there would be. The detailed motor repair sections are better for non-Vanos 4.4L. It is apparent that they tore down a 1997 or 1998 car in order to write many technical sections. Vanos is discussed with pics, but in less detail.
The electrical circuitry diagrams cover about 2/3 of book #2. About 99% of them should be applicable to M5. Lots of good ODBCII troubleshooting and code interpretation. Also, the various computers and data busses are described with nice block diagrams and genuine pics.
The book #1 has tons of chassis, body, dash, interior, drivetrain and suspension R&R detail that applies to M5. The beginning 1/4th of the book describes routine inspection and preventive maintenance procedures & tools with good detail.
This two book set is being sold for $110 and it blows TIS out of the water. Tons of pics, although some are a bit small. It augments TIS. It does not appear to be a clever rewrite of TIS, so the two complement each other.
Money well spent. I can not imagine how they are making money on this book, but thank god they wrote it. It was obviously time-consuming to write.
Hope this helps