trick the ecm for more hp

I have been browsing ebay for parts, and I have noticed several items that claim to boost hp and fuel economy by tricking the ecm into thinking that the intake air is always cold (46 F). Anybody have any comments on this?

Jai

You'll get better power but your gas milage will suffer.

Blake

And the power difference isn't all that great.:rolleyes:

its 23 degrees F here, don't need resistor