<p>Well, if you could easily score 800s on 5 or 6 SAT IIs go ahead and do it for your own pleasure. But getting 700s on 6 exams instead of 800s on 3 of them will not do you any good.</p>
<p>negative, unless you show breadth. A 750 in math 2 and a 750 in eng/humanities looks better to most colleges than 4x800 in sciences -- the exceptions being possibly CalTech and Harvey Mudd. Even MIT has english and history classes, and those profs want strong kids too. Thus, if you already have 3 strong science scores, a fourth Subject Test could strenghten your app if its not math-science.</p>