No. Do not buy from 3rd party websites. If you want to buy, PM Gunthar directly by clicking this link: https://bitcointalk.org/index.php?action=pm;sa=send;u=817682. Just tell him "I want to use the discount code ..." and send him your API key.

It does some with some default numbers, and it should work. For optimal performance you should be fine-tuning these settings and learning as you use the bot.

Yes. Frankly, I'd even recommend going with Bittrex over Poloniex (not an issue with the bot, but the exchange itself).

There are literally two above (Captain's and Mine).

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(Captain forgot to mention) Do not forget to register and read up on the content in the official community: https://gunthy.org/index.php.