Of course, www!=allintext. Do a search for a number of words (e.g. 'the'). Also, I believe that anchor text is still the most important part.
There is no general answer to this question. You have to find that out by yourself (by changing the occurrence / density of the keyword, Hx, bold, strong tags ...). However, even if the ranking for allintext is improved (while allinanchor and allintitle are unchanged), this doesn't mean that the ranking in the SERPS is improved.