I've done nothing to my TCR but on my previous PP I fitted a Racingline turbo elbow and intake pipe. Not a huge difference but noticeable so if you want to keep things simple I'd recommend them. Plus a nice bit of under bonnet eye candy 
Would you be able to give a rough price of how much that cost?. I'm thinking of changing a few things on my stock 14 GTi to make the engine noise sound better. Those parts might be an option or possibly just a RacingLine intake on it's own?
Then I can completely disable or massively reduce the soundaktor volume with OBD11
I've also done a bit or research on here about intakes and everyone seems to say "RacingLine or nothing" essentially. I know cheap ones will be rubbish with filtering and risk damage. There are a few other advanced options but the RL one just seems to be the most obvious and safest option