Regarding security audit: my day job is developing high security software. I could do a formal audit, and it would take about 2-3 person-weeks, and be completely useless, because it would result in a huge number of trivial issues that need to be resolved before it could identify real problems. So instead of wasting time and money on that, I've decided to go and fix those trivial issues one by one, and once I'm a bit happier with the code, I'll have two other people do the formal audit.