Is the cold weather. It help tremendous amounts on my car and the power output. My car pulls hard as it is but with it colder out (40's etc) it's a whole new car. It's damn fast and I love it 
One interesting side note. I drove my car for about an hour on the highway and when I got home I popped the hood to hook the battery charger up (cause it takes so much battery power to start it just helps to do that once a week or so) and felt my manifold and it was cold to the touch and then felt the throttle body and it was freezing cold but the rest of the engine was warm. That was really interesting and shows that heat dispursment atleast in my car is great because it's able to keep all induction componants very cold until it reaches the the ports in the head which all in all increases the POWA!!!!
One interesting side note. I drove my car for about an hour on the highway and when I got home I popped the hood to hook the battery charger up (cause it takes so much battery power to start it just helps to do that once a week or so) and felt my manifold and it was cold to the touch and then felt the throttle body and it was freezing cold but the rest of the engine was warm. That was really interesting and shows that heat dispursment atleast in my car is great because it's able to keep all induction componants very cold until it reaches the the ports in the head which all in all increases the POWA!!!!
