No it will not.
A warranty is a form of insurance and there are federal and state laws that regulate warranties.
A dealer can not void your warranty because you modded your car. They can deny your warranty claim for a specific issue , if your modification caused the problem in question.
If you are going to mod your car know your rights. Attach is the SEMA page on handling warranty issues.
http://www.semasan.com/main/main.aspx?id=60128
Most of the time you just have to say "
I know my right under the Magnusson Moss Warranty act and the case law" and the dealer will back off and do what is right