What is your reason for building an EV? I ask because it is important in deciding if it's worth doing it or not. I understand the thrill of a ride in a Tesla, but understand what you are going to be able to build with Lead Acid and $5k is more golf cart than Tesla...
Are you trying to save money? Forgettaboutit. Buy a used econobox and keep it gas.
Are you looking for performance? You will want lithium and a lot more cash.
Are you up for a different and neverending project just because it seems fun to do? That's more the mindset you'll need
spend a few hours (days?) reading the Wiki here, and check out a lot of cars at evalbum.com to see what has been done before, and what kind of performance you can expect with different component choices.