Either none, if the colleges to which you apply don’t require you to take the SAT subject tests, or one huge disadvantage, if you apply to a college that requires you to take them (elite colleges often require you to take two or three SAT subject tests). The huge disadvantage is that you won’t be accepted to those colleges that require them. Please check with the college(s) you’d like to attend, find out if they require SAT subject test scores when you apply, and plan accordingly.
Author: John Linneball Who did you think? ;-)
I'm the proprietor and only tutor for this business; that's why I named it after me.