You won't like what I have to say but I'll say it anyways.
First things first, most cold air intakes actually draw in hotter air than the stock airbox. Many modern cars have stock airboxes that actually draw air in from the wheel well or somewhere lower on the vehicle where the air is much cooler than the engine bay. The next thing is that most aftermarket cone-filters have a higher micron rating and allow MORE contaminants into your engine. I always recommend using a high-quality filter in your stock airbox.
Second thing is that a mass air flow sensor detects the amount of air entering your engine. Changing the sensor won't change the amount of air entering your engine. All changing the sensor will do is trick the computer into thinking it's getting more air flow which will cause the engine to supply more fuel. Your fuel economy will go down, the actual tailpipe emissions will go to crap, however you might notice a SLIGHT power increase. Whether or not it is worth it is up to you.