Well Ive been checking these out for a while and after handling one that was assembled I determined to pick one up. Let me say this, install will take a little while. The main reason is if you are still running a factory barrel you have to remove the front and rear sights. Also it comes with an extended mag release and bolt hold open. The fitment of the receiver shell is very snug, I actually had to sand a tiny bit to make it fit. But in the end the results are very worth it.