I will leave the more in-depth reviews to the readers with more engineering know-how; but I took delivery of this book from Amazon the other day, and as a first-timer to a BMW Bentley manual I'm quite impressed. At over 1400 pages there's no doubting that it's quite comprehensive and detailed. But for anyone who owns an E46 and has gone a step further to become an enthusiast, you will know how complicated these cars are; so it would appear impossible to cover absolutely everything for the E46, what with so many different body variations, engine options and equipment levels, not to mention different markets. Bear in mind that with the international context of use for this book, some details and specifics will be absent.
The pictures included are reasonably well detailed and are of high quality and of a decent size. Explanations are quite clear. A batch of wiring diagrams are appended to the end of the manual, which contributes substantially to its size. As those familiar with Bentley manuals will know, the manual is fully indexed and segmented into the main car components (e.g. engine; body), with each sub-component (e.g. changing the transmission; removing headlights) quite well-defined, including an overview of what special tools are required for the job.
I think this book will come in very handy for my E46 ('99 model) and would recommend it to friends. It's a bit expensive (though in reality this won't bother most people with E46s) and also this version is quite new so it may not breach the second-hand market in any great quantity in the near future.