here's the deal. 2 years ago i went to the track and my car ran 15.10 all stock accept for catback, pulleys, k&n in stock box, and chip. now the chip is gone plus but i have added everything in the sig and tonite i ran 15.19 @ 91 mph. why is it so slow? i should be in the mid to low 14's now. any suggestions on what to check? any help would be greatly appreciated. thanks