Originally Posted by Cyberium

I'll answer your questions before people start trying to kill you for not searching because they are pretty straight forward.

1. I'm not sure any intakes decrease MPG. It might seem like it because once people have them installed they like to redline their cars 90% of the time. Better air flow should = better MPG

2. With the Stillen G3 intakes you just need to enlarge holes on both sides. Injen intakes you don't have to cut anything, but you will need to replace your windshield washer fluid tank. Either way, you'll be doing some sort of modifying.

3. If your just doing intakes for now, you do not need a tune. Just disconnect your battery after install and let the ECU reset and it will adapt to the added airflow. You won't throw any codes as long as your MAF sensor is hooked back correctly and there are no leaks