definately remove the balance shafts, its not that hard and it shouldnt cost a whole lot either. I did mine the almost free way. pull the oil pump out with the shafts attached to it, remove the front shaft by unbolting it, get a freeze plug to plug the hole up and JB weld around it so it doesnt leak or come out. take an angle grinder and hack off the rear shaft but leave about an inch sticking out of the oil pump. there will be a hole in the center of the rear shaft so you must tap it out and put a bolt in it. or you could just not cut it off and go out and buy the stub shaft. take the balance shaft that you took out of the front one and use it to knock out the balance shaft bearings that are in the block, flip them 180 degrees so they block off the oil galleys (raises oil pressure- good thing), then use it to put them back in. the front doesnt have an oil galley hole so you can leave that bearing in. when you put the oil pump cover back on make sure you plug the holes where the old pulleys and gears went with bolts and use RTV on the bolts because it will leak if you dont.