2. Why would Google care what you call your domain?
3. So ling as your name is 'legal' - and your registrar could hardly sell you one that wasn't.
4. Google cares about the content of your site, and what you do with it. period.
Mind you, a long boring keyword-packed doamin name won't *help* you - and most potential visitors will run a mile. But that's a taste thing; in my view, best not to use spammers' domain naming conventions, lest people think, er, ...
For example, wordwordword.com in the url and word word word ised in the content should count as 6 references to it, or double the 3 you would expect.v