Here is my $0.02 on this. The most effective (and safest) way to manage fuel on any Nissan is to run a JWT ECU. If you want the ability to fine tune air/fuel ratios on your own, then also get the S-AFC. JWT tends to tune their turbo ECUs a little rich in order to prevent major catastrophes caused by overzealous boost junkies
With the S-AFC, you cannot alter or tweak ignition timing. However, there should be no need for this with the JWT ECU. The only timing mod you will need to make for more power under boost will be to run race gas and advance the timing to 20+ degrees BTDC.
If you plan on making serious power (like over 350 whp), I recommend the MSD 50 lb/hr injectors, 4 bar fuel pressure, and a Cobra or Z32 MAF. Of course, you can run drop-in Japanese side feed injectors with the 4 bar program, as long as you send an injector along with your ECU to JWT to have it flow tested. From that flow test, they can calibrate the injector pulse width needed to make the car run correctly.
If you want to keep the stock rail, get Apexi, Blitz, Tomei, etc....side feeds and the Nismo adjutable fuel pressure regulator, which bolts onto the OEM rail perfectly.
Lastly, I recommend staying with a MAF based engine management system. MAP based systems cannot compensate for sudden changes in engine volumetric efficiency, whereas a MAF can. This is why, on an RX-7, if you add a high flow exhaust, intake, downpipe, etc....you run the chance if running lean and detonating. The engine is now breathing in more air (at the same wastegate boost level) and the MAP sensor doesn't know it. The MAP sensor can only sense the pressure in the system, not the actual "amount" or mass of the air entering the engine.
The MAF can read the exact amount of air entering the engine and thereby relay this info the ECU, which will in turn keep the injectors open longer, supplying more fuel. If you get a large MAF, it will not be a restriction at all.
If you have unlimited free dyno access or deep pockets, stick with a MAF.
One more thing, I can get JWT ECUs faster than if you sent it in yourself. I am a JWT dealer and they are able to get my ECUs done a lot faster than if I were not a dealer.
I hope this info helps.
Later,