I've heard butt connectors create some resistance and was wondering if I were to join my esc to motor using butt connectors will it affect the performance at all?

Use something like this if you don't want the ESC soldered directly to the motor for some reason. Don't use the regular old crimp-on connectors.

http://www.amain.com/product_info.ph...-Male-2-Female

It certainly does but nothing to worry about unless you are a serious racer. Many of us have used some type of connector, usually some type of what is commonly used as a battery connector. If you do that just make the motor the male and the esc motor wire the female. Which is opposite of the battery. Won't be plugging stuff in backwards and such.