Bently Publishing has one thats very good (better than Haynes) or you could go with the factory shop manuals available at www.VolvoTechInfo.com and buy the complete set or just the ones purtaining to the area of what you're working on. If you order the factory manuals you only need the Motronic 4.3 manual if your car is a Turbo or you need the Fenix 5.2 manual if its a non-Turbo but don't order both. The factory manuals go into very detailed troubleshooting guides and indepth teardowns that your typical shadetree mechanic might not need. But if you want the best, get the factory manuals. Mike