While sitting around this weekend I decided to do a little research on a couple of issues;
1. Over servicing of K&N air filters. That myth is settled here;
http://www.knfilters.com/MAF/massairfindings.htm
2. Removal of the intake screen (reason for the thread). I've visited sites, read posts and learned about the different mass air flow sensors. We utilize the hot wire type. The wire is maintained at a constant temp and the air flow moving across it will cause it to loose heat faster. The ECU will compensate by sending more current and measures this current flow and puts out a voltage signal. This wire is made of platinum (hence the $250+ replacement cost) and is susceptible to damage if a foreign object should come in contact with it, (the screen). So are the internals of our engines, so if this happens I think the MAF is the last thing I would worry about.
The wire is self cleaning, (from what I read) at engine shut down this wire is heated to 1800 degrees to clean itself, unlike a dog that can lick his balls.
A couple GM forums had CFM numbers with and W/O the screens but the 180CFM difference was based on their size and density of screen. I know ours is restrictive and the filter I use will keep out anything harmful. As I've said, I will continue to run without. If a CEL occurs and its determined to from the MAF I'll post the results.