Ok, so the card warranty's intact, but presumably ripping off the stock cooler and sticking the Atomic block on your CPU could well leave you in the lurch if anything goes wrong in that department.
Certainly every PIB I've ever bought came with a warning that the use of anything other than the provided cooler or one from the list of approved coolers on the manufacturer's website would invalidate the warranty. Of course, you can always claim you *were* using the stock cooler, but then you can always screw the vanilla one back onto your graphics card too*.
Even less attractive then.
*Smart hardware monkeys take reference photos when dismantling and keep a variety of thermals pastes, pads and glues in stock to add veracity to this process.