My company started to do very unethical things (or maybe even break the law – I'm no expert) in order to cover up some business people fuckups. I'm seriously considering quitting immediately even though I hoped to stay here for some time as I like the people I work with. It's those unimaginative bastards at the top that make it unbearable.

Don't worry. If you like your current team as friends I think there's a good chance you'll keep in touch later.

I also had experience with horrible management, causing overtimes, burnout and stress. But this very bad experience is what brought us together. And now, after quitting 2 years ago, all of us are on our seperate ways - but we still get together regularly and laugh about these unpleasant times.

If it were me, I'd certainly start actively looking, but I wouldn't hand my notice in until I'd found somewhere else. You want to be out of there ASAP, but no point in leaving yourself short in the meantime.

I'd contact your integrity officer if the company is large enough to have one.