I have a Romanian WASR 10/63 double stack that this was put on. It is a pretty straight forward installation and was done in no time. I don't recall having to tweak anything to get it into place. MAN IS THIS GRIP COMFORTABLE! The rubber feel like it melts into your hand so you can shoot all day in comfort. It also has a much wider bottom than the original wood furniture, adding to the comfort level. You can choose to leave off the bottom rails (which I did). The gas tube cover ships with 2 pieces, 1 railed, 1 without so you can choose if you want the rails or not. They are molded, one-piece covers, so there's no rail screws to loosen up over time. The only down side is that there is no metal heat shield on the top piece, so that get warm in a hurry. I ended up drilling out some of the metal in the bottom heat shield and Dremelling some others to allow for more airflow, it helped a bit. The way it ships is a far improvement over the originals (but there's always room for tinkering). All in all, it's a great upgrade on the cheap. If you're tired of getting "hot hands" while shooting, this will help out greatly.
Pros: Easy to install, extremely comfortable
Cons: No top heat shield
This review was written in the old system and had content requirements that are different than reviews written today.