A-5 low-pressure kit

I was wondering, I am using air on my a-5. I have been doing some reading on the low-pressure kit. From what I understand it helps the a-5 handel the air pressure. I was going to go and install it and some one told me that I to by a regulator and something else to go with it for my tank. They told me it was to control the air flow. I thought that this is what the low-pressure kit was for?

Any help and or advise would be great.

I am slow but what does RVA stand for?

As far as the LP kit. Thanks for the info. I am a mostly a heavy gunner so the loud sound works for me. I am looking into getting a pistol for when i need to be quite.

Empirically, I found no change in efficiency when adding the LP kit.  I have heard similar results from others.

Theoretically, there is more space - that's what the LP chamber is for.  More space, less pressure = about the same amount of potential energy.  The paintball requires the same amount of energy to push, regardless of the pressure level of the air.  Lower pressure means a slightly longer burst of air, but the same amount of energy expended on the task.  There could be some savings on the blowback portion of the action, since the LP hammer is lighter, but if there is I don't see it.

But for any given mechanism, simply changing the pressure level does not automatically change the efficiency.  It might some of time - for instance, using a regulator to set the pressure level at "just enough" to get everything working at the desired velocity allows you to minimize waste, but that is difficult to do without combinging the reg with an RVA.