So, first mod i've done to my S4 was buy a giac ecu for my car, got it off of ebay so no wonder i'm having trouble. I am really looking forward to putting it in my car, but i don't know what tune the ecu is currently running. It has a stock tune, 93 octane tune, and 100 octane tune, i don't wanna put it in and have it be on the 100 octane tune and be using 93 octane, catch my drift?? So i'm wondering if anyone knows how to detect what tune my ecu is running, or if they can point me in the right direction? My car is going down within the next couple weeks for a timing belt job and new dv's. I would like to have it figured out by then

Please and thanks you's!

-Chris