The BK1 2.0 is a relatively simple platform, one that comes apart easily and has plenty of support! From basic bolt-ons to full turbokit assemblies to push high power, you have so many options to choose from.
Let's start with the basics. Assuming you know the terminology of the gen, abbreviations, etc. we'll start by going over the basic mods you can do.
--Intakes: One of the first mods people think of are intakes for their car. There are an abundance of intakes for the 2.0T out there, but many of them just stick the filter and intake in the engine bay. These are effectively "Warm air intakes" because they end up with heat soaked air from the engine bay. Intakes such as the Injen SP, HPS, etc. that are more of a "Short ram" system with a heat shield are like a bandaid. The stock intake box works well, since it's made of plastic, an insulator. Changing the filter over to a high flow K&N style filter will help with intake air temps. AEM, 3point8performance (3P8P) make ACTUAL cold air intake setups which route the filter away from the engine bay, sucking air in that is closet to ambient temps. If you want to add to that heat insulation, grab some reflective tape or ceramic coat the intake piping, which is aluminum (a conductor).
--Exhausts: Another popular mod that's easy to do is changing the exhaust system on your car. The sky is the limit here, with so many different combos. The basic power theme here is to have the least restriction in the exhaust while canceling out rasp and excess drone. Let's get one thing straight; STRAIGHT PIPING YOUR EXHAUST IS BAD. DO NOT DO IT. 9/10 people that do end up going a different route. The Theta (I and II) are LOUD and RASPY when straight piped. A quality exhaust system will sound aggressive AND will eliminate any restriction. Things like the ISR Race exhaust will give you a headache after 20-30 minutes of driving.*** Meanwhile, the Exceladyne turboback will give you a deep tone and will be more than adequate as a restriction-less system.
So you want to build your bk1 2.0