Don't add an intake to a turbo car with an ECU, it will do nothing. On a turbo car, you need to open up the exhaust first and get an ECU tune. You can sometimes get a decent gain with just an ECU tune, but the ECU controls everything, just adding an intake isn't going to fool the computer. There's all kinds of restriction in the intake, because it has to go through tiny holes in the turbo, through tubing, through the holes in an intercooler, then back up to the engine, to the intake manifold, and not only is the intake only one very small part of this, it doesn't matter, because the turbo compressor is what feeds the engine, by pressurizing the air. It's a different dynamic than a NA car, and even the "intakes" made for those cars tend to be a sham much of the time. It really doesn't benefit from an intake, unless you have done something like go to a bigger turbo that needs to feed more air, but turbos have certain volumetric efficiencies and can only move so much air, it doesn't do any good to try and give it "more". Many OEM intakes have some kind of silencer in them to cut down on noise and the short-ram intakes can provide you with more engine-noise-that's usually reason #1 that people think they are getting "more power". Also, on a lot of turbo cars, the engine bay stays relatively warm and at a stop, even "cold air" intakes tend to bring in relatively warm or hot air, despite their claims. I've had a few turbo cars before this and worked on my WRX quite a bit. In general, you want to free up the DP and turbo-back exhaust as much as possible, put a tune on it, and it will go pretty nice, using some of the leeway designed into the system, which can also make you go into "limp mode" in some hotter environments if you are running it hard. Axle-back exhaust is just for making noise. A bigger intercooler can help, but then your turbo has to fill a bigger volume, so it can cause more lag. As you are probably thinking, it gets to kind of be a never-ending game of chasing your tail. Your stock limits are generally governed by the amount of PSI the stock turbo can reliably produce and how much fuel the injectors and fuel pump can supply.
