Aurora R10, fan replacement Noctua NF-A12x25

The aftermarket fans will be quieter than the stock Dell fans, but they won't move more air.  The stock Dell fans are loud because they run at up to 4000 rpm and actually are rated to move more CFM than the aftermarket fans like the Noctua that run up to 2400 rpm.   The Noctua you mentioned is very popular for fan swaps in R10/R11/R12.  Thus, the quieter fans everyone talks about, but you won't move more air just by swapping the 2 stock fans out.   The benefits of getting more air are generally seen when you add an upper intake fan where the HDD bay is, so a new fan that Dell didn't put there to help with cool air intake (that's an easy to do with the y-splitter wire from Noctua and use the 3-pin end for the new fan, 4 pin end to the bottom original Dell fan, and just zip tie in the new fan where the HDD bay was).  Others also have done the radiator sandwich to add a pull fan on top of the radiator exhaust while also swapping out the Dell push fan that is directly below the radiator .   If you get the Bios error at startup just hit escape to bypass it.  I have seen posts that the Noctua fans may throw this error code, but the corsair pro non-rgb fans will not throw the code...check the reddit posts on R10/R11 fan replacements to be sure as lots and lots of people have done fan swaps to cut down on noise and in some cases get more airflow and better temps by adding more fans on the front and top.  The Noctua and the Corsair are the most popular from what it looks like on volume of posts and pictures on reddit and here.