The lowest junior engineer job grade at my previous company started at 50k + 8% bonus, and salaries went up to 90k base + 15% bonus for a principal engineer, with a pretty linear progression for the titles in between (mid-level, senior, lead). This company pays above average, but it's not the best paying in town, not even close. There are few ones (Amazon, eBay, SAP, car makers... even a few startups with deep pockets) that pay more than that.

If single, you will have a blast in Berlin with 45k. If you're moving with a dependent, that's a bit tight (as a newcomer, you will never find the best deals regarding accommodation, there's a fair supply of newly built apartments in Berlin, but they aren't cheap).

That's an exaggeration. Most salaries are places in the 50-60k range and if you are a senior you'll get a salary from 60-70k. As a new grad/junior, you'll be getting around 40-45k.

45k/year is enough for a single person or even a couple living more frugal.