This is a very good upgrade. The RT can shoot very very fast. You have to be careful not to shoot to fast to long or you will freeze the hose on the side of the a5 if you're using co2. This usually isn't a problem because most of the time you won't be shooting for to long. I loved my RT but I could never use it because all the fields in my area don't allow it.
For those of you thinking abotu getting the RT think about where you play. Ask your field if they allow it. If they don't get an e-grip.