If you get the AP, order from MazdaManiac. He provides a tuning service for free to ensure that you can get the right tune for your car, which will prevent what happened to your friend.

Was your friend's car an RX-8 as well? And when he used the new tune, where did he get it from? Basically, as long as the map you run your car on is done by a professional, your car should be fine. With MazdaManiac's maps, you'll actually get some features that improve reliability. Either your friend's car already had problems or he had a bad tune, because we haven't had anyone's car not able to run after installing an AP that I know of.

People here will typically support the AP more (as I'm sure you realize). If possible, I would agree that the AP is the better option. Especially if you can get one through MM and have him tune the map for you...

quicksilver, out of curiosity, what are you using this for? Are you going to be using it with a turbo or supercharger?