Ok, i am in the slow process of putting OBA in my rig (not much above stock, so i guess its not really a "rig") and I have a question. My friend has OBA and on his setup he has the air pumped into a "distribution box"
this box sends the air to a port in the front and read of the jeep. He connects a tank to the rear port, and then uses his tools off that. BUT, he also uses the front port which does not come from the tank. Is this bad. I hope this crude diagram can help explain it.

looks like alot of extra plumbing to me. if you feel the need for air at both ends of your truck, why not eliminate this "distribution box" and seperate it at the tank. But I really dont see the need for air at both ends.

It depends where (if at all) the check valve/unloaded is. If it's between the compressor and the distribution block then the whole block and front hose will still be pressurized from the tank. If it were between the distr block and the tank then the front hose would not be.

I don't really see the need for a front and rear connection either. for what it's worth.

:beer:

Like Xj4rocks said, if you dont have a check valve then you should still have full volume either way. but all yo have to do is put a manifold after the tank and run it out of there for both.
The only reason I ran mine front and rear is all you have to do is get a manifold. My quick connects came in a pack of 2 and I had the extra hose anyways, so why not, and if you have guys in front of you it is pushing it for a 50 foot coil hose to get to the front of a vehicle in front of you. either way you got to like options.;)