No it will not. The only way to void the warranty would be to mess with the hardware. That being said, Verizon will not officially offer you SOFTWARE support on an unapproved OS leak. If you had software problems, you would most likely need to downgrade back to the official OS before a VZW tech would help you. I say "officially" because you might get a tech that would still offer support with the leaked software.
But to answer your question, no it will not void the warranty and I 100% recommend the upgrade. Its a solid OS that fixed many bugs with the official .320. Please read the 101 series for upgrading your OS if your unfamiliar with the process. If you have any problems, there are plenty of experienced users here who should be glad to help you!
thanks very much for that info . i'm gonna read the 101 and the try to download . can you do it OTA ? and where is the best place to get the .428 leak ?