Is your Ender 3 now too small? Perhaps you’ve invested time and money getting it how you like it and don’t want to lose your tuned machine. Ender Extender kits retain much of the standard parts, but replace pieces of the frame to make the build volume much larger.
This was a pretty smooth install, some more pictures in the manual would be welcome but even in its current state this is very doable. The performance of the printer seems to be maintained but with a much larger build volume. Overall I am a fan of this mod because it represents great value for money over an off the shelf large format printer, with the bonus of being compatible with Ender 3 upgrades.