All Android devices should have unlocked bootloader (or have a way to unlock it without void warranty). Don’t stick with stock firmware only. And have the ability to install custom operating system software. Why? Stock ROM might not suite all of the users. Most of the custom ROM out there can be customized and tweaked for performance. Same apply to Google own smartphone ~ Nexus 4, you can unlock it easily (although it might void warranty but should not because you can lock it back). So why bother to stay on stock? Try out custom ones…
How to unlock Nexus 4 Bootloader?
The easy and simple way ~ use Google Nexus 4 ToolKit to do so. You can relock Nexus 4 bootloader with it too. By the way, do make sure that you have Nexus 4 ADB & Fastboot drivers installed first too.
Note – Unlock Nexus 4 bootloader will delete everything on your Nexus 4. Do backup all your data first.