5.9 magnum intake performance

One of my buddies is a machinest and builds motors and he had a Hughs intake on his truck. I had found one at a swap meet last year for $300 so I called to ask his opinion and he said he wouldn't waste the $300. Said it showed little or no gain in torque, drivability and fuel milage. I just walked on by it. I think all of these manifolds have potential to make power on a modified engine but none of them offer much on a stock or near stock engine.