Hey man, the circular dampener looking thing is a replacement pressure relief, stock Nissan item found on gtr's and comes with all tomei and nismo fuel pumps I believe to replace the factory plastic relief. No soldering required for this, plugged straight into the standard fuel hat plug. Have done the direct battery feed mod for the pump and the jet pump to the left in the picture is just insurance for the old stock plastic thing that draws fuel from the opposite hump side of the tank.
Hey just wanted to add this image here as there is none floating about on the correct layout for the sard jet pump in case anyone got confused by the manual on an R34 GTT 1999. Hope it can help someone out someday.