I do believe that my warranty with be void if i replace the HDD. So you are saying i should just keep the HDD and replace it anytime I need to use the warranty?If you bring it to the Genius Bar for service then they can blame whatever the problem is on the SSD as it did not come with the computer. I would keep the original hard drive in the event that you need to bring it in for service.
It's not voided per se, but it is true that they'll be resistant to repairing a machine that has 3rd party parts in it.
It doesn't void the warranty. But it does make it easier for them to say it's a problem with the SSD, so keeping the HDD around is a good idea just in case you need to take it in for repair. As someone else said, depending on what machine you buy next, you might want to use the SSD in that machine and sell your current MBP with the HDD back in it.