usually the AP maps are really rich not lean. I know too many people that have had problems with pulleys....that is something I will never put on my car....I don't care if it adds 20whp. Unless subaru makes it, it won't be going on. Those things usually have to be so perfectly balanced. I know a guy that had one....not a subaru, but still.....well it through off the oil pump and after about two minutes of driving without a working oil pump the engine was about as dead as they get.