Does Sleeving Corsair PSU Cables Void Warranty?

[shoota]

Sure, as long as you modify anything that comes with the product you are voiding your warranty (unless it is stated in the warranty policy).
With that said, if you want to sleeve psu cables without voiding the warranty of your psu you should look after psu's that are fully modular AND sell separate wires (there are some Silverstone models). This way, you can keep the originals and sleeve the replacements, so you keep the warranty because you didn't modify the psu nor the original wires.

If you are worrying about warranty (which is reasonable), you can just buy separated pre-made PSU modular cables or just the DIY parts (sleeves, heat-shrink, electrical wires and connectors) for your own sleeving and playing around.

Then you can ensure whole pack including cables can be returned to vendor in case of any problem happens in future.

You may search around the net and you'll find many options available, e.g. Corsair PSU Modular Cables

I'm not trying to be mean but 1) this thread is almost a year old and 2) what you said had already been said.

edit: Oh i see, you're advertising a website. Makes sense now :/