Well I got your previous post in my inbox

so I will tell you this, I don't know of its fuel saving qualities in which kind of weather, but as a short ram with a high-flow filter the intake does less work to get the air it needs and I can feel it. The engine rocks at high RPM no matter what weather. Obviously being a short ram and taking in hot air, it works a lot better when it's cold out, like it did just now and will even better later on

But that's all I know. It lets the engine breathe better at the higher points in the RPM band and it works better in cold weather. It will compliment the headers and test pipe rather well.