is there a less restrictive MAF on the market or is there a way to make the existing MAF more efficient? The whole door/paddle thinger seems dumb to me IMO.

 

apparently tho its better then the S5 ones. I think S5's can use the Mazda 929 ones. Not sure if we can. I suggest going with a Aftermarket ECU and getting rid of the AFM.

 

No, unless you want to try porting it. Just move it closer to the TB.

 

That won't make it any less restrictive. It will make it hotter though...

 

what kind of standalone aftermarket ECU would work well and be resonably priced?

 

Ouch, my brain...

First off, there isn't really anything wrong with the S4 AFM. I personally know several people with almost 400HP on the stock AFM, so it can't be all bad. And your NA GXL will never come close to maxing it out for flow. The S5 AFM is supposed to be worse then the S4 due to it's smaller diameter.

If you really, really want to get rid of the AFM, then something like the MAP-ECU is your only choice if you don't want to go full standalone. It's a small piggyback that repalces your AFM with a MAP sensor. For about $500. Does work reasonably well though...

Going further, there is a full standalone which completely replaces the stock EFI system. The price ranges from $140 to infinity with around $1000 being the norm. Keep in mind that it's a significant wiring job and then a good amount of time will be needed to make the car run properly (likely including dyno time).

 

if I remove my stock air intake and replace it with a CAI set-up...does the stock ECU automatically adjust the air/fuel ratio

 

MegaSquirt Plug n' Play?

 

no

 

This is true and I will have some dyno results to prove it in a few days when I get my dyno sheet emailed to me. There is this myth out there that the stock MAF is this super restrictive thing just waiting to be thrown away in order to give you gobs of horsepower, even on an N/A. Just tossing the AFM and going standalone (as compared to SAFC with CAS advanced) probably netted me 5hp with everything dialed in properly under WOT. The AFM does have its limits, but from personal experience it's not what everyone makes it out to be.