Seeing this discussion and seeing how there are people who want to debunk the fact that a Cold Air Intake can increase power without a tune, I have this to say.
When my car was stock, 1.4T Sonic RS with the factory Turbo Stage kit (148 HP), it drove differently under different conditions. Hot weather (90 plus degrees) and humid, it was a lot slower. Medium temps, the car was a bit quicker and more responsive, and when it is colder, in the 50's and 60's, I noticed a big difference. Why? Because the air is more condense and well, colder, when the temps are lower, thus giving the car (and almost all engines) better performance. Elevation (air density) has a lot to do with how a car performs, computer controlled (all cars are these days) or not.
So what does a Cold Air Intake do? If designed right, it allows for more air and colder air to get into the intake. My K&N Typhoon came with a shield to help block engine heat from getting to the air filter. There is a little air flow part that used to go directly into the old air box that comes from down under the front somewhere. It feeds right into where the new K&N filter sits. So the K&N system is getting direct outside air (so did the old box) into it. What does this mean? It means the intake going in just before the turbo gets more (meaning denser) and cooler (because there are not all these restrictions causing more heat) air.
It's been a couple days now and I still feel gains from just the addition of the K&N Typhoon. The computer hasn't altered settings to take those gains away, nor did it ever alter the settings and take the gain away on colder days of the year. Why would it do so for one situation and not the other? That doesn't make sense.
I will still stand with the fact the gains are pretty small....but they are there, especially at higher RPMs. My car feels about the same at lower RPMs, but as the turbo gains boost and the RPMs rise, I feel a good amount more pull than I did before.
For all my years knowing cars, from back in the carburetor days to the electronic age of the present, allowing cooler and more air into the intake has almost always improved power. Maybe not a ton of power, but some improvement.
But if you want more gain from any add on you do, a tune is something you should consider. The cost of a tune is pretty small. People say they can't afford a tune, which is only around $300 - $400, and I am like......really? The gains, especially with turbo cars, you get from a tune will be more than any other gains you can get from adding parts.
I am glad I got to experience my car with the K&N CAI on it for a few days before my Trifecta tune is ready. I really did want to see if the CAI alone did anything. Yes, it is much....much louder......in a good way in my opinion. Yes, it is a little quicker and I really feel the difference at higher RPMs.
Would just a CAI be worth the cost for the gains? For me, yes because even though the gains are small, it sounds bad ass! But I want big gains so I am doing both a CAI and a tune........and for a combination of $650 or so (Trifecta does a package deal if you buy both)......it is a lot of power for not that much money. I did get the elite tune (more expensive) so I can have it adjusted as needed.