As I suspected the air filter is not the problem. To learn more about filters, or to just see where different types of filters stand on flow and filtration, see:
http://www.bobistheoilguy.com/airfilter/airtest1.htm

Next test is to reinstall the factory airbox and check again- but I need to replace my rubber boot first. Anyone got one for sale?

I don't see your Spectre filter listed in that test. So how have you determined it'* not the problem, when cheap ricer knock-off'* have been KNOWN to be restrictions?
Is your filter one of the above? If not, that data is meaningless for your purposes. In addition, he tested OEM style drop-in rectangular filters. We primarily prefer a cylinder or cone shape to further increase surface area, particularly on cars with Superchargers that have far more airflow capability than his test car (Mazda Miata).

While I admire Bob, his methodology isn't a direct correlation to what we have or how we commonly set up our intakes.

I tested both a fresh out of the box K&N and running sans filter today, no change in max boost. Regardless of how you feel about my $16 filter it dosent look like it is the problem after all.

Im all for having a nice air filter, and its no doubt that K&N (I have had several in my time) is well known as the best flowing on the market, but for a daily driver Ill take a paper element filter please. Trouble is, I havent found someone who sells a paper element universal cone filter yet. And Im not gonna drop the extra $ on a new K&N until I find one when I can get something that filters just as well at the local auto parts store.

I think there are paper filters out there, something like CoolBlue, I know there blue in color.

Optmus, have you considered the possibility that your $16 filter was over-oiled at the factory, and the oil smoked your MAF sensor?

I'm not busting on you, but regardless of 'Bob', it'* a well-known fact in the performance community that a GOOD performance filter will outflow just about anything else, and a Mazda Miata is no 'flow' benchmark. A stock L36 or even L27 will out-flow a Miata.

If you're after performance, you can't 'afford' to go cheap. We've got years of experience on these cars and their setup. You'll do better in the wallet if you listen to what we've learned, instead of trying to re-learn it.

While I understand very well how you got a great deal on this setup, and you want to make the most of it, how much quality control and what type of materials could possibly have gone into that filter?

The filter came dry with a tiny (like less than 2oz.) spray bottle of oil. I only just oiled the filter last night (very lightly) and I have been noticing the low boost for several days (since installing the intake).

K&N outflows Spectre, Ill give you that. On the link above you can see that no filter at all outflows even K&N. I tested both the kn and no filter with no changes to my boost levels. Surely it seems the Spectre would flow better than my stock airbox and dirty Fram panel filter... Bill I know you can see my logic here. You just need to understand I wont buy a K&N unless I believe it is really my best choice- and right now I am sticking with what I have.

I linked to that information as a general FYI, any debate on that stuff (that isnt directly related to this stuff with my car) would be better suited for another thread.

Just curious, what kind of maximum boost level should I have? The ONLY mod to my engine prior to the intake was a 180 degree tstat.

7-8psi

Optimus..I'm looking through the post wondering the same thing you are...why are you having trouble by swapping an intake.

When you did the swap you were in an area with many vacuum lines. I'd suggest checking them. Also if possible check to make sure when your car heats up that the septic pipe coupler doesn't bend or restrict in any way.

I carefully checked all vac. lines when I swapped out the BCS the other night.

For some reason, I have been able to actually get back up to normal boost today a few times. Not consistantly though.

OK, after a tank'* worth of driving there has been no great change in MPG, which is what I expected based on other factors related to vehicle tune and recent driving conditions. Not to mention all those sprited test drives to see where my boost peaked at. Speaking of which, boost is peaking where it should and as far as I know, when it should so thats seemed to sort itself out. I have some more research to do on that later.

So testing out the $35 intake setup has gone pretty well, next I think Ill test stock airbox with a K&N drop-in maybe? Maybe Ill "gut" it and try running a paper replacement. The idea of a FWI with some ridid piping, unlike the INTENSE design (not that theres anything wrong with their'*) has been floating around too, as well as building a heat shield box for my short ram with some ductwork...