My advice: buy it. That sounds like a great deal for someone like you that doesn't mind doing their own work. That was the case with me when I got my 330xi with 120k on it, everyone was telling me it was going to be a money pit but so far the only things I have done are regular oil changes myself and I did the rear brakes. I love working on this car anyway. You're plan to get a PPI is a good idea too.
2006 330xi 6MT - Deep Green Metallic/Beige Dakota - Every Option but Sports Package. No mods.