Thanks for the help guys. After browsing the forum for a while I've decided to go with the 1518. I really like the 1717 due to it's size but from what I have read it's a power hungry motor. My 2s 35C 3800 packs probably won't do it.
Worst case I'll buy both but I'll most likely go with the 1518. I can always bump the voltage in the future.