I wouldn’t necessarily say that your tuner is wrong with respect to maf readings. It is true that under SOME conditions the air will be more turbulent with an aftermarket air intake than with the factory intake. The factory goes through great lengths to ensure the airflow has as little turbulence as possible and the result can be observed in the relatively smooth maf signals present in most stock applications.

With that said, an intake that produces more flow will in fact produce more power since the air mass consumed is larger and a larger amount of fuel will need to be added to hit the desired fuel targets. A good measurement without a dyno can be approximated by logging g/s of air consumed by the engine under identical conditions for comparison.

Ultimately a lower turbulence maf signal will produce a more accurate load calculation and that will produce a smoother ignition timing curve and the car will drive smoother than a high turbulence system. Each implementation has its drawbacks/benefits.

I'd say coilovers unless you want hp gains then get a 3" intake and a tune. Most 3" intakes require a tune for the car to actually run well.

Stillen Gen 3 Intake
 

I am selling my Stillen Gen 3 intake if you are interested. Only has about 200 miles on it.

Fast Intentions Turbo kit

IMO:
1. Zspeed CSC Elimination Kit
2A. Intake Either a CAI or K&N Drop ins; Our stock intake is pretty good at getting cold air but the tubing isn't the greatest. 2B. ECUtek Tune
3. Wavetec or Quaif Differential
4. Front Sway Bar
5. Tires and brake pads and oil cooler
6. Done or Take a dive down the rabbit hole of $$$

Install a Z Speed Performance CMAK before it’s too late and install a oil cooler kit for starters.

You drinking the coolaid? For the Z, the gains from CAI from Stillen and Takeda are documented.