If you're driving around in a big-HP car with a "pegged" stock MAF and you've been told that it's safe to do so......you might be in for a big surprise ($$$$)! Even if your air/fuel ratio was optimized on a dyno, when the environmental conditions differ than those on the day that your car was tuned (i.e. altitude, humidity, temperature = density variations) your air/fuel ratio can become overly rich or even worse DANGEROUSLY LEAN potentially leading to a damaged motor. The MAFXtender™, when coupled with your stock MAF, can give you the range that you need to keep your PCM in complete control of the air/fuel mixture while your engine makes big horsepower.
Please note that use of the MAFXtender™ requires extensive retuning of your vehicle!!!!!