A real slow site may have issues. Best bet it to create your pages with low overhead to increase response to users and the bots.
I wouldnt really say it had an impact, but a quickly loading web page does help spiders read the content much quicker. Regardless of SEO, use 1 css style sheet for the layout and styling of all pages, this will then cache in the users browser and make pages load at lighting speed.
Not too much but if it takes too much time for a webpage to load then there is problem you should look into As I said above it will not help you anyway in getting higher ranks in Search Engine
As long as it loads eventually for the GoogleBot to index it. If you're asking if Google takes your website uptime into consideration, I HIGHLY doubt it...
The only way response speed will have any effect whatsoever is if GoogleBot's requests timeout. You can see if/when this is happening in their Webmaster Tools under Diagnostics.
IMO... the faster the page load, the better it is. play safe. get a very good hosting provider, and good uptime. make the page below 100kb, will help as well. spider is program, so they are hardcoded with timeout, basically, they not tolerate in waiting or downtime