I run a HKS ssqv on my CA18det. I ran it to atmosphere for 10 minutes (I felt like a dick with the car making all those noises), before I got onto the lathe and turned up an alloy adapter to plumb it back. I copied the picture of the plumb back adapter from pictures on ebay.

AFM(MAFM) reside in front of the turbo and throttle body. They tell the ECU how much air is entering the engine, so fuel can be tuned to suit.
MAP sensor accepts only a vaccuum signal and it not a critical part of the intake.

MAP sensed engine can run atmo BOV.
AFM/MAFM need to run plumb back BOV so all the air entering the engine is being measured properly.

AFM equipped engines will backfire down exhaust due to over-fueling as air is lost via the blow off valve. The ECU measure the air, and setup fuel for it, but the air was wasted out of the BOV, resulting in an over rich mixture.