I installed a K&N Cone air filter #RU-3610 , for a very effective cold air intake,after removing the entire airbox. This is a HUGE air filter. It filled the space of the air box and is a perfect fit onto the oxygen sensor tube. I paid $50.00 Canadian. I also removed the negative battery cable, and reconnected it, so the ECU would recognize the change. The change in acceleration is huge and very surprising! It also makes good grumbling sound on acceleration. I think the large size of the air filter, and the lack of tubing, is allowing a large volume of air into the intake. I did this before with another Aveo, using a smaller cone filter from RAid. The results were poor and only slightly better acceleration. I also ported a silicone line from a shielded cone high flow filter into the fender air port for a true cold air intake. Again. poor results. If you want an easy inexpensive boost in power, remove the air box, and attach the K&N #RU-3610.