[Apex Motorsports]

Here is a link to an article from Edmunds.com that also covers this topic. Below is the relevant text from that article.

Aftermarket parts or modifications: This aspect of warranty coverage has a great deal of gray area. Although many dealers would have you think otherwise, simply having an aftermarket part or modifying your vehicle cannot void your warranty.

"Some dealerships may say 'just because you have a [cold air] intake or something' that the whole vehicle warranty is voided," explains Loren Wong, Edmunds associate business analyst and a former warranty administrator for BMW and Acura. "That's not true."
The saving grace for consumers is the Magnuson-Moss Warranty Act of 1975. The act states that a dealer must prove that aftermarket equipment caused the need for repairs before it can deny warranty coverage.

However, if the reason for a parts failure is unclear, a dealer will usually charge you to diagnose the vehicle. If the aftermarket part was not properly installed or a modification led to a component failure, it is within the dealer's right to void the warranty for that part, and you will have to pay for the repairs out of pocket. If the aftermarket parts had nothing to do with the repairs in question, you will be refunded the fee for the diagnosis.

Any aftermarket performance parts on your vehicle can cause a dealer to suspect that you either drive the car hard or possibly race it. "Although they may not void warranties," Wong added, "modifications may raise a red flag when vehicles are in for service. If consumers who mod their cars do a little research, they may find certain dealerships that are a little more 'mod-friendly.'"

Here is a link to a consumer information article posted by the US Federal Trade Commission on their website. Below is the relevant text from that article.

Will using 'aftermarket' or recycled parts void my warranty?

No. An 'aftermarket' part is a part made by a company other than the vehicle manufacturer or the original equipment manufacturer. A 'recycled' part is a part that was made for and installed in a new vehicle by the manufacturer or the original equipment manufacturer, and later removed from the vehicle and made available for resale or reuse. Simply using an aftermarket or recycled part does not void your warranty. The Magnuson-Moss Warranty Act makes it illegal for companies to void your warranty or deny coverage under the warranty simply because you used an aftermarket or recycled part. Still, if it turns out that the aftermarket or recycled part was itself defective or wasn't installed correctly, and it causes damage to another part that is covered under the warranty, the manufacturer or dealer has the right to deny coverage for that part and charge you for any repairs. The FTC says the manufacturer or dealer must show that the aftermarket or recycled part caused the need for repairs before denying warranty coverage.

Tips To Avoid Warranty Issues

Here's how to get the most out of your vehicle's warranty:

Read your warranty - Often bundled with your owner's manual, the warranty gives a general description and specific details about your coverage. If you have misplaced your owner's manual, look for it online.

Check the "Owners" section of your manufacturer's website. -
Be aware of your warranty period. If problems arise that are covered under the warranty, get them checked out before the warranty expires.

Service your car at regular intervals - This is a good idea in any case. But for the sake of keeping your warranty intact, follow the manufacturer's recommended service schedule. Details are in your owner's manual.

Keep all service records and receipts, regardless of who performs the service - This includes oil changes, tire rotations, belt replacement, new brake pads, and inspections. Create a file to keep track of repairs; it will come in handy if you have to use your warranty. If you ever have a warranty claim and it appears that you did not maintain your vehicle, your claim could be denied.

Complain - If you think a dealer's service advisor denied your warranty claim unfairly, ask to speak with a supervisor. If you still aren't satisfied, contact the manufacturer or go to another dealer. You also may wish to file a complaint with your state Attorney General, local consumer protection office, or the FTC.

Here is a quote posted here on Camaro5 by one of the Chevrolet Customer Service Reps in response to a warranty question.

Originally Posted by Chevrolet Customer Svc

Modifications or tunes do not automatically void the powertrain warranty, but in many cases they will. If there is an issue or damage, and it is found to be the result of a modification or tune, then your powertrain warranty will be found void. These products may have detrimental effects on the performance and life of the engine, exhaust, emission system, transmission, and drivetrain. I hope this helps.

Reggie B.
Chevrolet Customer Care