Well guys i picked up a x4 tuner for 140 bucks and i figured you cant beat that. It is just a basic tuner and is not linked to any tuning company. I plugged it up and turned off my rear O2 sensors however I had to select an octane rating. I just picked 87 because thats what was in it. Did it change anything other than the o2 sensors like timing and fuel? I assume it would if i picked 93. Also, what is a good fan settting? Would it be useful to change it? Thanks guys.