Interesting developments in the semi-hacker-tech Android space: XDA-Developers forum member "kszaq" posted a nice FAQ / Guide on how to replace certain system libraries on your Nexus Device with Moto X versions.Apparently by comparing benchmarks the tech-folk discovered that the Moto X scores better than similar devices with Android 4.4 KitKat. By taking the library-innards apart people found optimized versions of  Bionic and Dalvik.Bionic is a google-created derivative of the Linux standard C library. It is supposed to make developer's lives easier. A Linux developer group called "Code-Aurora-Group" has optimized the standard library so it works faster on Qualcomm's Snapdragon platform. Google really should use this optimized version in the Android platform but so far it hasn't.The optimized Dalvik library would replace the usual Android-Runtime Compiler. This optimized version seems to be developed by Qualcomm itself and it is closed source. The specific nature of the Qualcomm optimizations is unclear but what's interesting is: the optimization is so good that this quicker Dalvik library runs even better then the next generation ART compiler.The Android hacker community now took these optimized versions from the Moto X firmware and made them available for installation and use on Nexus 4, 5 or 7. Relying on these versions would increase performance by some 5-10% on Qualcomm devices.Rooting your Android is not required - detailed instructions are in the XDA-Developers post.

• basically you need to read all: http://forum.xda-developers.com/showthread.php?t=2546120 (download links included)
• you most likely would void your warrenty
• you need to have Android 4.4 KitKat on your device
• to make things easier you should have a Custom Recovery running
• then (still read the full xda post) upload the provided files to your device
• flash the images over your current ROM using the custom recovery