Q: The Audi A4 2.0T is a 2006. I would like to find ways to add power but not lose my warranty. Perhaps a chip that can be inserted without activating the check engine light.
A: There are alot of things you can do to increase the performance of you car. 1. Chip/Turbos What most people do is they first chip it. You can either go with GIAC or APR both are really great chips, however I'd go with the GIAC just because you can switch back to your original software if you needed to get a smog check. Because your engine is turbocharged, you can also go for an APR k04 turbo upgrade which you can get for about $1500 if you figure tuning, exhaust and turbo. 2. Downpipes and Cat-Backs What most people do afterwards is to get downpipes and catbacks, which will increase the flow of your exhaust and give you that nice growl :). Milteks have been the all around #1 best company for these, however, Neuspeed has recently made a higher quality and louder by a couple decibels for the Audi S4. I believe the Neuspeed ones can also be put on on the Audi A4. Also the the Neuspeed ones are cheaper than the Milteks. 3. Intake/ Air Filter What most people do after this is to add the intake. The intake will increase your mileage by a bit and due to the increase air flow, you exhaust will sound even louder and sicker :). There are two good intakes, Stratmosphere's and Carbonio. Both do the same job, it's just that Carbonio charges $100 more since it comes with a carbon fiber cover. 4. Suspension, Rims etc After that you can spend money on suspension and rims to increase the performance on your ride. Hope this helps :)