I'm fresh out of high school so I'm working more hours now and making more money, I want to mod my base model 2.0T 2006 A4. The problem is I don't know where to start, new CAI or an ARP chip, bigger turbo. Can I get some help, where do I start?

 

A cold-air intake has little gain on these engines. Go with a chip. Many of them have similar performance and you can probably just go with whoever is close to you to do the programming.

Honestly, if you're straight out of high school and driving a 2006 Audi, you should probably not do anything to it until you have at least $2500 in savings for all the maintenance and repairs it will cost you in the next couple years.