Hi all, I have now acquired all the kit I need to watercool my 2 RX480s. One is a Sapphire 8gb reference card and the other is a Powercolor 8gb reference card. I plan to add alphacool gpx blocks to these cards and they are both listed as compatible. What I want to know is, should I tell/ask the manufacturers above about warranty with an aftermarket cooler. Or, should I say nothing and if a problem arises (bearing in mind I have stress tested both gpus to test them) then replace the stock cooler and rma?