Few questions about applying early at Columbia University?

<p>Originally, I was going to apply ED to increase my chances. However, the more I research it the more it looks like it doesn't make a huge difference. Yet even a slim chance in getting a (tiny) upper hand in applications in such a competitive school (7% acceptance rate, Ivy) makes me want to apply ED still. I pose two problems:</p>

<p>1) My SAT score is low for Columbia standards, it is 1930. Would it be better to apply RD and hopefully bring up my scores or apply ED and have an increased (if that's true) chance.
2) I will need financial aid. I have used the net price calculator and attended an info session, both basically confirming that the aid will meet my needs. Everyone suggest not to apply ED if you may not be able to afford it, but I have read twice now that since I am applying for aid, I don't have to withdraw my other apps until I know the aid package for Columbia, is this true? </p>

<p>My stats, in case this helps you get a feel for whether I'm adequate:
-ranked 10th in a class of 204
-weighted GPA of 103 as of the end of last year, currently around 106 if that matters
-3 APs, 1 Honors (my school doesn't offer many)
-many extracurriculars
-will receive my subject tests scores tomorrow, but I don't expect them to be excellent nor terrible</p>