For $2, I would think of getting one for a back-up, if I didn't already have enough back-ups.
If I understand your question about the resistors, you should be fine. Just make sure you understand the instructions and follow them. If you run across one you don't understand, just post a question here.
If I understand your question about the resistors, you should be fine. Just make sure you understand the instructions and follow them. If you run across one you don't understand, just post a question here.