From: Ol' Blighty
1). Actually, since the final patch of Vanilla DW I've never had a single crash. It was bad before that, in-fact I still keep autosave on 15 mins (it used to be 10) because of fear of crashes, but in all honesty, vanilla DW final patch was over a year ago and I've never got a crash since then. I hardly ever see a bug either, the only serious bug I have experienced was in the last beta patch for Legends, which has been fixed in the current one. There have been many issues that are not bugs that have caused concern (like area weapon friendly fire, fuel range of freighters, population growth of independent planets for example), but not many actual technical bugs. Most issues and bugs are addressed by Eliott quickly, he's good!
2). The game is not demanding on graphics card at all, so it really doesn't matter. 4GB of RAM should be fine to run the large galaxys too. Game relies on processor, yours will probably be okay, this isn't a demanding game. However, I overclocked my i5 the other day and saw a massive performance improvement. Framerate generally won't be an issue, the expansion planner and shiplists can take a few seconds to load up in longer games where there is a lot of info to load. But, your rig should be totally fine for DW, also, performance has improved since its original release.
3). Say goodbye to your loved ones, give your boss the finger and prepare to launch!!!!!!
"My body may be confined to this chair, but my mind is free to explore the universe" - Stephen Hawking