The only time I would consider buying used is if the parts are being sold by Paul Grant. I have purchased from Paul several times and it's always a pleasure to deal with him. He will not sell you junk, he is more than fair, and he will help you if you need advice.

If Trevor sold used I would buy from him as well, he's another individual who has integrity and will do right by you.

 

Provide a clear written description of the condition you require, require a written confirmation of condition, pay with a credit card and there's little to no risk.