I am very satisfied with Carista. I'm using it with a cheap veepeak VP-01 OBD connector I got on Amazon, and my Ipad. The app connected immediately and downloaded all the available customized settings......no more than 20 seconds. I made quite a few changes, and each saved within 5 seconds. No need to disconnect/reconnect the adaptor each time. I went right from one setting to the next. In the end, I tested each of the changes, and they all stuck. Considering $16 for the adaptor and $20 for the app, I couldn't be happier.
No more seat belt warnings and eco light. Windows roll down with remote and with finger on handle. Lock chirp is much quieter. AC does not come on each time I press the auto button, doors all lock/unlock together, etc. Lots of great customizable settings.