If you install it correctly and get your dealershi pto verify it then you still have full warrenty. Same thing with my GMPP intake. I bought of CED and installed it myself. They still cover my entire warrenty, because I have the sticker and verification that it is a GM part.
It shouldnt create any problems anyways, unless you install it wrong.

 

dude i had the same exact problem when i got my stage 2....there was NO dealership that wanted to do it...AND they said it would void my warranty as well...i even called chevy DIRECTLY and they said it would void it as well!! BUT than i emailed gm performance parts themselves and they stated that if installed by a dealership the cobalt stage kits DO NOT void the warranty. SO after days of searching i found a dealer that knew what they were doing and knew it did NOT void the warranty...paid about 300 for the install...550 for the parts....good luck

 

I paid $650 installed for my kit. I have installed a stage kit before on a friends car that was already out of warranty and it was easy. I wanted my warranty because I travel so much I had the dealer do mine. I talked to the tech at the local dealer ran him through what the dos and donts alerted him of any hang ups and the car was in and out in about an hour. The install that I did was about 2 hours including the trip to a local machine shop. To me I just couldn't see paying a **** ton of money for someone to install something that I was completely capable of doing, so I just had to haggle with them. The only requirement that the service manger set was that I had to take him out for a ride when I picked the car up. Before I left he went in and talked to the new car manager and had him order 2 one for him and one for the lot. I don't know if he ever bought one but there were two there withing that same month. I just thought that was cool.

 

here is where i got mine from http://www.crateenginedepot.com/stor...P1540C196.aspx
about $1000 all said and done (roughly)

 

uhh no you dont u can install it yourself and get them to reflash it and your fine...