Wouldn't that really mess up the Mass Airflow Sensor? I don't know, I've heard bad things about this. There are some testing this and a Home Depot product that does the same thing. Lets see what they say. Other applications like this are used in PVC piping for plumbers and stuff like that
In a way I feel bad for these guys spending $255 US on the blower fans. I find it hard to see someone pass over that much money on a device which they know nothing about, no brand names, specs or substantial evidence that it's a performance modification besides a person on ebay for that matter telling them it works. That's as bad as the person that payed $10 for an empty coke can.