Honestly, it's all preferences. A lot of people prefer the long range barrel, while a lot of people prefer the reinforced barrel. For the sake of it, you should try out each barrel and see what you like. I recommend not putting on the Recoil Control Stock because it gives your para a bit side to side recoil. I have been using the SA58 Para since it was released. I know what I'm talking about.
NEVER use the heavy barrel, just don't do it. And like gotswag said, Para is really up to preference. Easiest setup is definately spets barrel plus whatever you feel like. I do recommend that you use the grip in your setup, as it has no negative side effects.