Welp, technically, what I'm {cough cough} advising {cough cough} you to do is illegal to begin with, because technically all of us rooted folks have in fact voided our warranty, but TECHNICALLY that really does not constitute a Warranty void IMNSHO b/c TECHNICALLY (in Technicolor) (sorry, had to go there), with the ability for all of us to revert to pure stock, that cannot and should not be deemed as a warranty voiding action in the first place.
So, while normally I would not condone such illegal activity, I cannot agree with the principle on which this voiding of the warranty is based in the first place, so I'll stand my ground.
If you have water damage / physical damage to the phone, I'll tell you to suck it up and pay to buy a new one / replacement / different phone, but I draw the line on rooting....